BlackMark
a285347e5f
R/r/w/F collapse into G and g over a selector byte naming the space — flash,
EEPROM, data, fuse, SPM — with the flash bank in its high nibble. Four command
bodies, four transfer loops and four argument decodes become one of each, and
W joins the same decode instead of keeping an address form of its own. The
loader shrinks while gaining everything below: on the 1284P the stock build
goes 480 -> 432 B and the software one 496 -> 450.
What the freed space buys:
- Data space. On AVR one pointer spans SRAM, the register file and the whole
I/O space, so G over space 2 reads all three. pureboot keeps zero static
RAM and pushes no register, so at loader entry an application's SRAM is
still what the application left there — this is a post-mortem, not just a
poke hole. As its own command it needed a dispatch arm and a loop; as one
more space it is a single ld/st.
- Host-issued SPM. W fills the page buffer and stops; erase, write and RWW
re-enable are writes to space 4, which reach the same fused store-and-SPM
pair through the transfer's own address and data. Any SPM operation, lock
bits included, is now reachable and the loader carries no page-commit logic.
The four-cycle SPMCSR-to-SPM window is why that primitive stays fused: no
host can hit it across a serial link, and that — not the byte count — is
the floor on how low-level a bootloader's primitives can go.
- Byte addresses everywhere. The bank in the selector retires the
word-addressed wire the >64 KiB parts needed, so the 1284s stop being the
outlier.
SERIAL autobaud is a third backend on the same loader, over libavr's
software_autobaud: no clock, no baud, one binary per chip for every F_CPU and
every rate. Activation counts poll iterations rather than seconds and bounds
every wait, so a stray pulse cannot hold an unattended device.
b answers with the version and signature only; the host derives geometry from
the signature, which is what an autobaud build requires anyway. An update image
is a bare slot with no device to ask, so every image carries a six-byte stamp —
the same bytes b answers with, and the source of both — that the loader never
reads from flash and the host refuses to install a mismatch against. The
running-slot write guard moved onto the SPM commit, which covers erase and
write both where guarding W covered neither directly.
The position-independence lint now proves the property instead of a proxy for
it: the image must come out byte-identical linked at a different base.
-fno-move-loop-invariants left the tuned flag set — it was fitted to a command
loop carrying four transfer bodies and costs bytes now that it carries one.
Verified: the exhaustive matrix on all 37 chips (every clock x every baud x
every backend, non-standard rates included, plus the autobaud build) —
8174 size checks, no failures, tightest fit the 1284s' autobaud at 510 of 512.
Behavioral suites green on every chip class: t13a 10/10, t85 11/11, m8 13/13,
m16a 13/13, m48pa 13/13, 328P 23/23, 644A 17/17, 1284P 17/17. Data-space
round trip through --peek/--poke and the autobaud handshake are both red-green
proven.
The two prototype sources and their findings file go; the README carries the
protocol and dev/done.md in libavr carries the reasoning.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
1387 lines
61 KiB
Python
1387 lines
61 KiB
Python
#!/usr/bin/env python3
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"""pureboot host tool — the smart half of the protocol (README.md).
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The device exposes primitives; everything composite is here: HEX/raw images,
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programming with repairing read-back verification, the reset-vector surgery
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the boot-section-less chips need, and the self-update that stages the loader
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one slot lower and lets it rewrite the resident.
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Standard library only. The port is termios on POSIX and the Win32 serial API
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through ctypes on Windows, so any tty or COM port works.
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"""
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import argparse
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import json
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import os
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import sys
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import time
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if os.name == "nt":
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import ctypes
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from ctypes import wintypes
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else:
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import select
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import termios
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PROMPT = b"+"
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VERSION = 4 # this tool's own version — free to drift from a loader's
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# The loader versions this tool speaks. A pureboot version implies its wire
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# protocol, which carries no number of its own, so this window is where that
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# map lives: every version so far speaks the same protocol, and one that
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# changes it becomes the new floor here.
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OLDEST_LOADER = 1
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NEWEST_LOADER = 5
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SLOT = 512 # the loader slot, on every chip
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RETRIES = 3 # rewrites of a page that reads back wrong, before the run stops
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# pureboot 5 replaced the four per-memory commands with one pair: 'G' reads and
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# 'g' writes, each taking a selector byte, a 16-bit address and a count, over
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# the spaces below. The loader carries one transfer loop instead of four bodies
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# — which is what buys the data space and the host-issued SPM operations.
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UNIFIED_LOADER = 5
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SP_FLASH, SP_EEPROM, SP_RAM, SP_FUSE, SP_SPM = 0, 1, 2, 3, 4
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# A selector's high nibble is the flash bank — the address bits above the 16-bit
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# wire address — so a transfer names a byte address within one 64 KiB bank and
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# no command has to speak word addresses. No single transfer may cross a bank
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# boundary; the host chunks to keep that true.
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def selector(space, address):
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return space | ((address >> 16) << 4)
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# The SPM operations pureboot 5 leaves to the host: a write to SP_SPM hands its
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# byte to SPMCSR and fires the instruction at the selected flash address. Every
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# part pureboot targets agrees on these encodings.
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SPM_ERASE, SPM_WRITE, SPM_RWWSRE = 0x03, 0x05, 0x11
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# Calibration byte for an autobaud loader: 0xC0 is a start bit plus six zero
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# data bits — one low pulse of seven bit-times, which the loader times into its
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# per-bit unit. Sent at whatever baud the host chose; the loader locks to it.
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CALIBRATE = 0xC0
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# pureboot 5 answers 'b' with its version and the chip signature; the host
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# derives the rest of the geometry from the signature rather than reading a
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# table off the device. flash, page, eeprom, patch-vector per distinct
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# signature, over every chip pureboot targets (the loader computes the same
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# from its chip database at build time). Die revisions that share a signature
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# share this row, as they share the silicon.
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CHIP_GEOMETRY = {
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# signature : (flash, page, eeprom, patch_vector)
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(0x1E, 0x90, 0x07): (1024, 32, 64, True), # ATtiny13/13A
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(0x1E, 0x91, 0x08): (2048, 32, 128, True), # ATtiny25
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(0x1E, 0x92, 0x06): (4096, 64, 256, True), # ATtiny45
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(0x1E, 0x93, 0x0B): (8192, 64, 512, True), # ATtiny85
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(0x1E, 0x92, 0x05): (4096, 64, 256, True), # ATmega48/48A
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(0x1E, 0x92, 0x0A): (4096, 64, 256, True), # ATmega48P/48PA
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(0x1E, 0x93, 0x07): (8192, 64, 512, False), # ATmega8/8A
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(0x1E, 0x93, 0x0A): (8192, 64, 512, False), # ATmega88/88A
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(0x1E, 0x93, 0x0F): (8192, 64, 512, False), # ATmega88P/88PA
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(0x1E, 0x94, 0x03): (16384, 128, 512, False), # ATmega16/16A
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(0x1E, 0x94, 0x06): (16384, 128, 512, False), # ATmega168/168A
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(0x1E, 0x94, 0x0B): (16384, 128, 512, False), # ATmega168P/168PA
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(0x1E, 0x94, 0x0A): (16384, 128, 512, False), # ATmega164P/164PA
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(0x1E, 0x94, 0x0F): (16384, 128, 512, False), # ATmega164A
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(0x1E, 0x95, 0x02): (32768, 128, 1024, False), # ATmega32/32A
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(0x1E, 0x95, 0x0F): (32768, 128, 1024, False), # ATmega328P
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(0x1E, 0x95, 0x14): (32768, 128, 1024, False), # ATmega328
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(0x1E, 0x95, 0x08): (32768, 128, 1024, False), # ATmega324P
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(0x1E, 0x95, 0x11): (32768, 128, 1024, False), # ATmega324PA
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(0x1E, 0x95, 0x15): (32768, 128, 1024, False), # ATmega324A
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(0x1E, 0x96, 0x09): (65536, 256, 2048, False), # ATmega644/644A
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(0x1E, 0x96, 0x0A): (65536, 256, 2048, False), # ATmega644P/644PA
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(0x1E, 0x97, 0x05): (131072, 256, 4096, False),# ATmega1284P
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(0x1E, 0x97, 0x06): (131072, 256, 4096, False),# ATmega1284
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}
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VERBOSE = False
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def verbose(message):
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if VERBOSE:
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print(f" {message}")
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class Error(Exception):
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pass
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class Progress:
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"""A transient bar on stderr, drawn only for a tty and erased when done —
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logs and pipes see only the summary line each operation prints. No label
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or a zero total disables it, so callers can pass one unconditionally."""
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def __init__(self, label, total, unit="pages"):
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self.label, self.total, self.unit = label, total, unit
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self.done = 0
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self.width = 0
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self.live = bool(label) and total > 0 and sys.stderr.isatty()
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self._draw()
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def __enter__(self):
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return self
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def __exit__(self, *exc):
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if self.live:
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sys.stderr.write("\r" + " " * self.width + "\r")
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sys.stderr.flush()
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def step(self, n=1):
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self.done += n
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self._draw()
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def _draw(self):
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if not self.live:
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return
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bar = 24 * self.done // self.total
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line = (f"{self.label:<16} [{'#' * bar}{'-' * (24 - bar)}] "
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f"{100 * self.done // self.total:3d}% {self.done}/{self.total} {self.unit}")
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self.width = max(self.width, len(line))
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sys.stderr.write("\r" + line)
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sys.stderr.flush()
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# ---------------------------------------------------------------- serial ---
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class PosixPort:
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"""A raw serial port with deadline-based reads, over termios."""
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def __init__(self, path, baud):
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self.fd = os.open(path, os.O_RDWR | os.O_NOCTTY)
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attrs = termios.tcgetattr(self.fd)
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attrs[0] = 0 # iflag
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attrs[1] = 0 # oflag
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attrs[2] = termios.CREAD | termios.CLOCAL | termios.CS8 # cflag
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attrs[3] = 0 # lflag
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try:
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speed = getattr(termios, f"B{baud}")
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except AttributeError:
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raise Error(f"unsupported baud rate {baud}") from None
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attrs[4] = attrs[5] = speed
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attrs[6][termios.VMIN] = 0
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attrs[6][termios.VTIME] = 0
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termios.tcsetattr(self.fd, termios.TCSANOW, attrs)
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def close(self):
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os.close(self.fd)
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def write(self, data):
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os.write(self.fd, data)
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def flush_input(self):
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termios.tcflush(self.fd, termios.TCIFLUSH)
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def read_available(self, wait):
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"""Everything that arrives within `wait` seconds of quiet start."""
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ready, _, _ = select.select([self.fd], [], [], wait)
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return os.read(self.fd, 4096) if ready else b""
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def read_exact(self, count, timeout):
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data = b""
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deadline = time.monotonic() + timeout
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while len(data) < count:
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remaining = deadline - time.monotonic()
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if remaining <= 0:
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raise Error(f"timeout: got {len(data)} of {count} bytes")
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ready, _, _ = select.select([self.fd], [], [], remaining)
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if ready:
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data += os.read(self.fd, count - len(data))
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return data
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if os.name == "nt":
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# The same port, over the Win32 serial API — kernel32 through ctypes, so
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# the tool stays standard-library only. Timeouts live in the driver
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# (COMMTIMEOUTS) rather than in a readiness call: Windows has no select()
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# for a COM handle, so each read asks the driver for its own deadline.
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_GENERIC_READ, _GENERIC_WRITE = 0x80000000, 0x40000000
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_OPEN_EXISTING, _PURGE_RXCLEAR = 3, 0x0008
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_INVALID_HANDLE = wintypes.HANDLE(-1).value
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# A gap this long ends a read_available(): longer than the coalescing a
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# USB-serial adapter's latency timer imposes (16 ms on FTDI parts), so a
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# burst is not split, short enough to stay responsive.
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_GAP_MS = 30
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class _DCB(ctypes.Structure):
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_fields_ = [
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("DCBlength", wintypes.DWORD),
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("BaudRate", wintypes.DWORD),
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("fBits", wintypes.DWORD), # the packed flag bitfield, set below
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("wReserved", wintypes.WORD),
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("XonLim", wintypes.WORD),
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("XoffLim", wintypes.WORD),
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("ByteSize", wintypes.BYTE),
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("Parity", wintypes.BYTE),
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("StopBits", wintypes.BYTE),
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("XonChar", ctypes.c_char),
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("XoffChar", ctypes.c_char),
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("ErrorChar", ctypes.c_char),
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("EofChar", ctypes.c_char),
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("EvtChar", ctypes.c_char),
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("wReserved1", wintypes.WORD),
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]
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class _COMMTIMEOUTS(ctypes.Structure):
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_fields_ = [
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("ReadIntervalTimeout", wintypes.DWORD),
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("ReadTotalTimeoutMultiplier", wintypes.DWORD),
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("ReadTotalTimeoutConstant", wintypes.DWORD),
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("WriteTotalTimeoutMultiplier", wintypes.DWORD),
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("WriteTotalTimeoutConstant", wintypes.DWORD),
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]
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_k32 = ctypes.WinDLL("kernel32", use_last_error=True)
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_LPDWORD = ctypes.POINTER(wintypes.DWORD)
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# Declared, not inferred: a HANDLE is a pointer, and a defaulted int
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# return would truncate it on 64-bit.
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_k32.CreateFileW.restype = wintypes.HANDLE
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_k32.CreateFileW.argtypes = [wintypes.LPCWSTR, wintypes.DWORD, wintypes.DWORD,
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wintypes.LPVOID, wintypes.DWORD, wintypes.DWORD, wintypes.HANDLE]
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_k32.ReadFile.argtypes = [wintypes.HANDLE, wintypes.LPVOID, wintypes.DWORD, _LPDWORD, wintypes.LPVOID]
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_k32.WriteFile.argtypes = [wintypes.HANDLE, wintypes.LPCVOID, wintypes.DWORD, _LPDWORD, wintypes.LPVOID]
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_k32.GetCommState.argtypes = [wintypes.HANDLE, ctypes.POINTER(_DCB)]
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_k32.SetCommState.argtypes = [wintypes.HANDLE, ctypes.POINTER(_DCB)]
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_k32.SetCommTimeouts.argtypes = [wintypes.HANDLE, ctypes.POINTER(_COMMTIMEOUTS)]
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_k32.PurgeComm.argtypes = [wintypes.HANDLE, wintypes.DWORD]
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_k32.CloseHandle.argtypes = [wintypes.HANDLE]
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def _fail(what):
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code = ctypes.get_last_error()
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raise Error(f"{what}: {ctypes.FormatError(code).strip()} (Windows error {code})")
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class WindowsPort:
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"""A raw serial port with deadline-based reads, over Win32."""
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def __init__(self, path, baud):
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# Win32 takes the rate as a plain integer, so unlike termios any
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# rate the hardware can divide down to is available — but a driver
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# may also accept one it cannot produce (an FT232R takes a baud of
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# 3, reports it back, and goes on using the previous divisor).
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# Only obvious nonsense is refusable; the rest is the driver's word.
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if baud < 50:
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raise Error(f"unsupported baud rate {baud}")
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# \\.\COM6: the device-namespace form. A bare COMn resolves only
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# for n < 10, and double-digit ports are routine on Windows.
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if path.lower().startswith("com") and path[3:].isdigit():
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path = rf"\\.\{path}"
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self.handle = _k32.CreateFileW(
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path, _GENERIC_READ | _GENERIC_WRITE, 0, None, _OPEN_EXISTING, 0, None
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)
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if self.handle == _INVALID_HANDLE:
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_fail(f"cannot open {path}")
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self.timeouts = None
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try:
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dcb = _DCB()
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dcb.DCBlength = ctypes.sizeof(_DCB)
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if not _k32.GetCommState(self.handle, ctypes.byref(dcb)):
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_fail(f"cannot read the state of {path}")
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dcb.BaudRate, dcb.ByteSize, dcb.Parity, dcb.StopBits = baud, 8, 0, 0 # 8N1
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# fBinary, and DTR/RTS asserted (fDtrControl and fRtsControl,
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# two bits each, = _ENABLE); every other flag clear, so no
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# parity and no flow control. Raising both matches what opening
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# a POSIX tty does — including the reset pulse on the boards
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# that wire DTR to it.
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dcb.fBits = 0x1 | (1 << 4) | (1 << 12)
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if not _k32.SetCommState(self.handle, ctypes.byref(dcb)):
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_fail(f"cannot configure {path} for {baud} baud 8N1")
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# Arm them once here too: reads re-arm per call, but the write
|
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# timeout would otherwise stay at the driver's default — which
|
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# may be "wait forever" — until the first read.
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self._deadline(_GAP_MS, 1000)
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except Error:
|
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# An open port outlives the exception otherwise, and a COM
|
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# handle is exclusive: the next attempt would meet its own
|
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# leftover as "Access is denied".
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self.close()
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raise
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|
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def close(self):
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_k32.CloseHandle(self.handle)
|
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|
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def _deadline(self, interval, total):
|
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"""Arm the driver's read timeouts: `interval` ms of quiet ends a
|
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read once bytes have arrived, `total` ms ends it regardless."""
|
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if self.timeouts == (interval, total):
|
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return
|
|
spec = _COMMTIMEOUTS()
|
|
spec.ReadIntervalTimeout = interval
|
|
spec.ReadTotalTimeoutConstant = total
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spec.WriteTotalTimeoutConstant = 5000
|
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if not _k32.SetCommTimeouts(self.handle, ctypes.byref(spec)):
|
|
_fail("cannot set the port timeouts")
|
|
self.timeouts = (interval, total)
|
|
|
|
def _read(self, count):
|
|
buffer = ctypes.create_string_buffer(count)
|
|
got = wintypes.DWORD()
|
|
if not _k32.ReadFile(self.handle, buffer, count, ctypes.byref(got), None):
|
|
_fail("read failed")
|
|
return buffer.raw[: got.value]
|
|
|
|
def write(self, data):
|
|
written = wintypes.DWORD()
|
|
if not _k32.WriteFile(self.handle, data, len(data), ctypes.byref(written), None):
|
|
_fail("write failed")
|
|
if written.value != len(data):
|
|
raise Error(f"short write: {written.value} of {len(data)} bytes")
|
|
|
|
def flush_input(self):
|
|
if not _k32.PurgeComm(self.handle, _PURGE_RXCLEAR):
|
|
_fail("cannot flush the input buffer")
|
|
|
|
def read_available(self, wait):
|
|
"""Everything that arrives within `wait` seconds of quiet start."""
|
|
# A zero total means *no* timeout to the driver, so never round
|
|
# down to it — the same trap on the deadline below.
|
|
self._deadline(_GAP_MS, max(1, round(wait * 1000)))
|
|
return self._read(4096)
|
|
|
|
def read_exact(self, count, timeout):
|
|
data = b""
|
|
deadline = time.monotonic() + timeout
|
|
while len(data) < count:
|
|
remaining = deadline - time.monotonic()
|
|
if remaining <= 0:
|
|
raise Error(f"timeout: got {len(data)} of {count} bytes")
|
|
# No interval timeout here: only the count or the deadline
|
|
# ends the read, so a gap mid-reply is simply waited out.
|
|
self._deadline(0, max(1, round(remaining * 1000)))
|
|
data += self._read(count - len(data))
|
|
return data
|
|
|
|
|
|
Port = WindowsPort if os.name == "nt" else PosixPort
|
|
|
|
|
|
# -------------------------------------------------------------- protocol ---
|
|
|
|
|
|
class Info:
|
|
"""The 12-byte info block."""
|
|
|
|
@classmethod
|
|
def from_identity(cls, raw):
|
|
"""pureboot 5's reply: the version and the chip signature. The rest of
|
|
the geometry is looked up from the signature — the loader derived the
|
|
same facts from its chip database at build time, so nothing is guessed,
|
|
it is simply not sent. Reconstructs a block in the older layout, so
|
|
every derived attribute below is shared with the loaders that do send
|
|
one.
|
|
|
|
The base is where application flash ends, which is a property of the
|
|
chip and not of the copy answering: a loader staged one slot lower
|
|
reports the same geometry the resident one does, exactly as the loaders
|
|
that send a block do. Which slot a copy runs in matters only to its own
|
|
write guard, which is the loader's business."""
|
|
if len(raw) != 4:
|
|
raise Error(f"bad identity reply: {raw.hex()}")
|
|
version, signature = raw[0], tuple(raw[1:4])
|
|
geometry = CHIP_GEOMETRY.get(signature)
|
|
if geometry is None:
|
|
sig = " ".join(f"{b:02x}" for b in signature)
|
|
raise Error(f"unknown signature {sig} — this tool has no geometry for it")
|
|
flash, page, eeprom, patch = geometry
|
|
base = flash - SLOT
|
|
word_flash = flash > 0x10000
|
|
wire_base = base // 2 if word_flash else base
|
|
flags = (1 if patch else 0) | (2 if word_flash else 0)
|
|
raw12 = bytes((ord("P"), ord("B"), version, *signature, page & 0xFF,
|
|
wire_base & 0xFF, wire_base >> 8, eeprom & 0xFF, eeprom >> 8, flags))
|
|
return cls(raw12)
|
|
|
|
def __init__(self, raw):
|
|
if len(raw) != 12 or raw[0:2] != b"PB":
|
|
raise Error(f"bad info block: {raw.hex()}")
|
|
self.version = raw[2]
|
|
if not OLDEST_LOADER <= self.version <= NEWEST_LOADER:
|
|
raise Error(
|
|
f"pureboot {self.version}: this tool (version {VERSION}) speaks pureboot "
|
|
f"{OLDEST_LOADER}..{NEWEST_LOADER} — a newer loader needs a newer tool"
|
|
)
|
|
self.raw = bytes(raw)
|
|
self.signature = raw[3:6]
|
|
self.page = raw[6] or 256 # the wire count convention: 0 means 256
|
|
self.patch_vector = bool(raw[11] & 1)
|
|
# Bit 1: the flash runs past what one 16-bit address covers. Through
|
|
# pureboot 4 that made flash addresses words on the wire; pureboot 5
|
|
# keeps them bytes and carries the bank in the selector instead. Every
|
|
# address in this tool stays a byte address either way and converts at
|
|
# the wire.
|
|
self.word_flash = bool(raw[11] & 2)
|
|
scale = 2 if self.word_flash else 1
|
|
self.base = (raw[7] | (raw[8] << 8)) * scale
|
|
self.eeprom_size = raw[9] | (raw[10] << 8)
|
|
self.flash_size = self.base + SLOT
|
|
self.stage = self.base - SLOT # where a staging copy of the loader goes
|
|
# The hand-over target as 'J' takes it: the trampoline below the
|
|
# loader, or word 0 where BOOTRST re-vectors reset in hardware.
|
|
self.app_entry_word = (self.base - 2) // 2 if self.patch_vector else 0
|
|
|
|
def describe(self):
|
|
sig = " ".join(f"{b:02x}" for b in self.signature)
|
|
vector = "host-patched reset vector" if self.patch_vector else "hardware boot section"
|
|
return (
|
|
f"signature {sig}, page {self.page} B, "
|
|
f"app flash {self.base} B (loader at {self.base:#06x}), "
|
|
f"EEPROM {self.eeprom_size} B, {vector}"
|
|
)
|
|
|
|
def lines(self):
|
|
"""One fact per line — what --info prints."""
|
|
if self.patch_vector:
|
|
hand_over = f"host-patched reset vector, trampoline at {self.base - 2:#06x}"
|
|
else:
|
|
hand_over = "hardware boot section, jump to word 0"
|
|
return (
|
|
f"version pureboot {self.version}",
|
|
f"signature {' '.join(f'{b:02x}' for b in self.signature)}",
|
|
f"flash {self.flash_size} B, {self.page} B pages"
|
|
+ (", past one 16-bit bank" if self.word_flash else ""),
|
|
f"application 0x0000..{self.base - 1:#06x} ({self.base} B)",
|
|
f"loader {self.base:#06x} ({SLOT} B slot)",
|
|
f"staging {self.stage:#06x}",
|
|
f"EEPROM {self.eeprom_size} B",
|
|
f"hand-over {hand_over}",
|
|
)
|
|
|
|
|
|
class Loader:
|
|
"""A session. Between commands the loader has prompted and awaits a
|
|
command byte; every method restores that, except jump() — after which the
|
|
target must be knocked afresh."""
|
|
|
|
def __init__(self, port):
|
|
self.port = port
|
|
self.info = None
|
|
# Set once a session is established over an autobaud link, so a
|
|
# re-entry after 'J' repeats the handshake that worked.
|
|
self.autobaud = False
|
|
|
|
def _read_identity(self):
|
|
"""The 'b' reply, in either of the two layouts a loader may send.
|
|
pureboot 5 answers with its version and the signature; older loaders
|
|
answer with a 12-byte block. The version byte cannot be mistaken for
|
|
the older block's 'P', so four bytes are enough to tell them apart."""
|
|
head = self.port.read_exact(4, 2.0)
|
|
if head[0:2] == b"PB":
|
|
return Info(head + self.port.read_exact(8, 2.0))
|
|
return Info.from_identity(head)
|
|
|
|
def _handshake(self, wait, knock, what):
|
|
"""One activation, retried until the loader answers or the window
|
|
closes. The identity reply is what proves the loader is listening — a
|
|
prompt byte alone does not, since one left over from a previous session
|
|
can still be in the pipeline while the port opening resets the device
|
|
into a fresh window, where a command without its knock is discarded.
|
|
Each attempt is therefore the whole handshake. This also converges into
|
|
an already-live session: the knock bytes are ignored there and the
|
|
drain absorbs whatever they produced."""
|
|
deadline = time.monotonic() + wait
|
|
knocks = 0
|
|
while True:
|
|
self.port.flush_input()
|
|
self.port.write(knock)
|
|
knocks += 1
|
|
if PROMPT in self.port.read_available(0.4):
|
|
while self.port.read_available(0.3):
|
|
pass
|
|
self.port.write(b"b")
|
|
try:
|
|
# A version the tool cannot speak is the loader's own
|
|
# answer, not a failed knock: Info reports it rather than
|
|
# sending the tool round the loop again.
|
|
self.info = self._read_identity()
|
|
except Error as failed:
|
|
if "pureboot" in str(failed):
|
|
raise
|
|
self.info = None
|
|
if self.info is not None:
|
|
self._expect_prompt()
|
|
verbose(f"loader answered {what} {knocks}; identity read")
|
|
return self.info
|
|
if time.monotonic() > deadline:
|
|
raise Error("no answer — reset the device within its activation window")
|
|
|
|
def connect(self, wait):
|
|
"""Knock 'p' then 'b' and read the identity."""
|
|
return self._handshake(wait, b"pb", "knock")
|
|
|
|
def connect_autobaud(self, wait):
|
|
"""The autobaud handshake. In place of the p+b knock the host sends the
|
|
calibration pulse — one seven-bit-time low pulse at the host's chosen
|
|
baud, which the loader times into its per-bit unit — then a single 'p'
|
|
the loader decodes at the rate it just measured. A lost pulse, or a
|
|
knock landing while the loader is mid-frame, simply fails to answer and
|
|
leaves the measurement loop waiting for the next pulse, so the retry in
|
|
_handshake covers it."""
|
|
self.autobaud = True
|
|
return self._handshake(wait, bytes((CALIBRATE, ord("p"))), "calibration")
|
|
|
|
def _expect_prompt(self, timeout=2.0):
|
|
byte = self.port.read_exact(1, timeout)
|
|
if byte != PROMPT:
|
|
raise Error(f"expected prompt, got {byte.hex()}")
|
|
|
|
def _command(self, tx, reply_len=0, timeout=2.0):
|
|
self.port.write(tx)
|
|
reply = self.port.read_exact(reply_len, timeout) if reply_len else b""
|
|
self._expect_prompt(timeout)
|
|
return reply
|
|
|
|
def _stream_read(self, command, address, count, address_scale=1):
|
|
data = b""
|
|
while count:
|
|
chunk = min(count, 256)
|
|
wire = address // address_scale
|
|
head = bytes((ord(command), wire & 0xFF, wire >> 8, chunk & 0xFF))
|
|
data += self._command(head, chunk, 5.0)
|
|
address += chunk
|
|
count -= chunk
|
|
return data
|
|
|
|
@property
|
|
def unified(self):
|
|
"""pureboot 5 and later: one 'G'/'g' pair over selector-named spaces."""
|
|
return self.info is not None and self.info.version >= UNIFIED_LOADER
|
|
|
|
def _read_space(self, space, address, count):
|
|
"""A run out of any space, chunked to 256 bytes and to bank bounds."""
|
|
data = b""
|
|
while count:
|
|
chunk = min(count, 256, 0x10000 - (address & 0xFFFF))
|
|
head = bytes((ord("G"), selector(space, address), address & 0xFF,
|
|
(address >> 8) & 0xFF, chunk & 0xFF))
|
|
data += self._command(head, chunk, 5.0)
|
|
address += chunk
|
|
count -= chunk
|
|
return data
|
|
|
|
def _write_space(self, space, address, data, progress=None):
|
|
"""A run into any space. Each byte is acked as its write begins — an
|
|
EEPROM cell and an SPM operation both need that pacing, and the ack is
|
|
what the loader sends in place of a completion status."""
|
|
offset = 0
|
|
while offset < len(data):
|
|
chunk = data[offset : offset + min(256, 0x10000 - (address & 0xFFFF))]
|
|
head = bytes((ord("g"), selector(space, address), address & 0xFF,
|
|
(address >> 8) & 0xFF, len(chunk) & 0xFF))
|
|
self.port.write(head)
|
|
for byte in chunk:
|
|
self.port.write(bytes((byte,)))
|
|
self._expect_prompt()
|
|
if progress:
|
|
progress.step()
|
|
self._expect_prompt() # the next command prompt
|
|
address += len(chunk)
|
|
offset += len(chunk)
|
|
|
|
def spm(self, operation, address):
|
|
"""One SPM operation at a flash address — the erase, write and RWW
|
|
re-enable that pureboot 4 ran inside 'W' and pureboot 5 leaves here."""
|
|
self._write_space(SP_SPM, address, bytes((operation,)))
|
|
|
|
def read_ram(self, address, count):
|
|
"""Data space: SRAM, and with it the register file and every I/O
|
|
register, which share the address space on AVR. New in pureboot 5."""
|
|
return self._read_space(SP_RAM, address, count)
|
|
|
|
def write_ram(self, address, data):
|
|
self._write_space(SP_RAM, address, data)
|
|
|
|
def read_flash(self, address, count):
|
|
if self.unified:
|
|
return self._read_space(SP_FLASH, address, count)
|
|
if not self.info.word_flash:
|
|
return self._stream_read("R", address, count)
|
|
# Word-addressed wire: widen to even bounds and never let one read
|
|
# cross a 64 KiB boundary (the device holds RAMPZ for a whole run).
|
|
start = address & ~1
|
|
span = (address + count + 1 & ~1) - start
|
|
data = b""
|
|
at = start
|
|
remaining = span
|
|
while remaining:
|
|
chunk = min(remaining, 0x10000 - (at & 0xFFFF))
|
|
data += self._stream_read("R", at, chunk, address_scale=2)
|
|
at += chunk
|
|
remaining -= chunk
|
|
return data[address - start : address - start + count]
|
|
|
|
def read_eeprom(self, address, count):
|
|
if self.unified:
|
|
return self._read_space(SP_EEPROM, address, count)
|
|
return self._stream_read("r", address, count)
|
|
|
|
def write_page(self, address, data):
|
|
assert len(data) == self.info.page and address % self.info.page == 0
|
|
if self.unified:
|
|
# 'W' fills the page buffer and stops there; the erase and the write
|
|
# are host-issued SPM operations. Only a chip with a boot section
|
|
# has RWW to re-enable — on the others bit 4 of SPMCSR means
|
|
# something else entirely, so it must not be sent.
|
|
head = bytes((ord("W"), selector(SP_FLASH, address), address & 0xFF, (address >> 8) & 0xFF))
|
|
self._command(head + data, 0, 2.0)
|
|
self.spm(SPM_ERASE, address)
|
|
self.spm(SPM_WRITE, address)
|
|
if not self.info.patch_vector:
|
|
self.spm(SPM_RWWSRE, address)
|
|
return
|
|
wire = address // (2 if self.info.word_flash else 1)
|
|
head = bytes((ord("W"), wire & 0xFF, wire >> 8))
|
|
self._command(head + data, 0, 2.0)
|
|
|
|
def write_eeprom(self, address, data, progress=None):
|
|
if self.unified:
|
|
self._write_space(SP_EEPROM, address, data, progress)
|
|
return
|
|
offset = 0
|
|
while offset < len(data):
|
|
chunk = data[offset : offset + 256]
|
|
head = bytes((ord("w"), address & 0xFF, address >> 8, len(chunk) & 0xFF))
|
|
self.port.write(head)
|
|
for byte in chunk:
|
|
self.port.write(bytes((byte,)))
|
|
self._expect_prompt() # per-byte ack: the write has begun
|
|
if progress:
|
|
progress.step()
|
|
self._expect_prompt() # the next command prompt
|
|
address += len(chunk)
|
|
offset += len(chunk)
|
|
|
|
def read_fuses(self):
|
|
if self.unified:
|
|
return self._read_space(SP_FUSE, 0, 4)
|
|
return self._command(b"F", 4, 2.0)
|
|
|
|
def jump(self, word_address):
|
|
"""The device acks, then execution continues at the word address."""
|
|
self.port.write(bytes((ord("J"), word_address & 0xFF, word_address >> 8)))
|
|
self._expect_prompt()
|
|
|
|
def enter_copy(self, byte_address, wait):
|
|
"""Jump into the loader copy at `byte_address` and knock it — a slot
|
|
base is that copy's entry stub, so it can only land there."""
|
|
autobaud = self.autobaud
|
|
self.jump(byte_address // 2)
|
|
return self.connect_autobaud(wait) if autobaud else self.connect(wait)
|
|
|
|
def run_application(self):
|
|
self.jump(self.info.app_entry_word)
|
|
|
|
|
|
# ---------------------------------------------------------------- images ---
|
|
|
|
|
|
def load_image(path):
|
|
"""Raw binary, or Intel HEX by extension (.hex/.ihx/.ihex)."""
|
|
data = open(path, "rb").read()
|
|
if not path.lower().endswith((".hex", ".ihx", ".ihex")):
|
|
if not data:
|
|
raise Error(f"{path}: empty image")
|
|
return data
|
|
memory = {}
|
|
for number, line in enumerate(data.decode("ascii", "replace").splitlines(), 1):
|
|
line = line.strip()
|
|
if not line:
|
|
continue
|
|
if not line.startswith(":"):
|
|
raise Error(f"{path}:{number}: not an Intel HEX record")
|
|
record = bytes.fromhex(line[1:])
|
|
if sum(record) & 0xFF:
|
|
raise Error(f"{path}:{number}: checksum mismatch")
|
|
count, address, kind = record[0], (record[1] << 8) | record[2], record[3]
|
|
payload = record[4 : 4 + count]
|
|
if kind == 0:
|
|
for i, byte in enumerate(payload):
|
|
memory[address + i] = byte
|
|
elif kind == 1:
|
|
break
|
|
elif kind in (2, 4) and not any(payload):
|
|
continue # a zero base extends nothing
|
|
elif kind in (3, 5):
|
|
continue # start address: irrelevant, reset is the entry
|
|
else:
|
|
raise Error(f"{path}:{number}: record type {kind} reaches beyond the 16-bit space")
|
|
if not memory:
|
|
raise Error(f"{path}: empty image")
|
|
return bytes(memory.get(i, 0xFF) for i in range(max(memory) + 1))
|
|
|
|
|
|
# --------------------------------------------------------------- surgery ---
|
|
|
|
|
|
def rjmp_target(word_address, opcode, flash_words):
|
|
return (word_address + 1 + (opcode & 0x0FFF)) % flash_words
|
|
|
|
|
|
def rjmp_to(word_address, destination, flash_words):
|
|
return 0xC000 | ((destination - word_address - 1) % flash_words % 0x1000)
|
|
|
|
|
|
def plan_flash(image, info):
|
|
"""The pages to program, as {page_address: bytes}, already carrying the
|
|
reset-vector surgery where the chip needs it."""
|
|
page = info.page
|
|
limit = info.base - (2 if info.patch_vector else 0)
|
|
if len(image) > limit:
|
|
raise Error(f"image is {len(image)} B, application flash ends at {limit}")
|
|
final = bytearray(image) + bytearray([0xFF] * (-len(image) % page))
|
|
|
|
if info.patch_vector:
|
|
flash_words = info.flash_size // 2
|
|
word0 = final[0] | (final[1] << 8)
|
|
if word0 & 0xF000 != 0xC000:
|
|
raise Error(
|
|
"the image's reset vector is not an rjmp — pureboot's vector "
|
|
"surgery cannot re-home it (crt-less entry at address 0?)"
|
|
)
|
|
entry = rjmp_target(0, word0, flash_words)
|
|
if entry >= info.base // 2:
|
|
raise Error(
|
|
"the image's reset vector already targets the loader — this "
|
|
"is a read-back of a patched image; flash the original"
|
|
)
|
|
trampoline_word = (info.base - 2) // 2
|
|
patch = rjmp_to(0, info.base // 2, flash_words)
|
|
final[0], final[1] = patch & 0xFF, patch >> 8
|
|
trampoline_page = info.base - page
|
|
if len(final) < trampoline_page + page:
|
|
final += bytearray([0xFF] * (trampoline_page + page - len(final)))
|
|
jump = rjmp_to(trampoline_word, entry, flash_words)
|
|
final[info.base - 2], final[info.base - 1] = jump & 0xFF, jump >> 8
|
|
verbose(f"vector surgery: word 0 -> loader {info.base:#06x}, "
|
|
f"trampoline {info.base - 2:#06x} -> entry word {entry:#06x}")
|
|
|
|
pages = {a: bytes(final[a : a + page]) for a in range(0, len(final), page)}
|
|
return pages
|
|
|
|
|
|
def covered(pages, info, skip_blank):
|
|
"""Pages in programming order, optionally dropping all-0xff ones (sound
|
|
only over erased flash, and never a load-bearing page).
|
|
|
|
A patched vector puts page 0 first and the trampoline page second, so from
|
|
the first write on a reset lands in the loader and its fall-through on the
|
|
application entry — every interruption point recoverable. A hardware boot
|
|
section re-vectors reset regardless; page 0 goes last there, which
|
|
maximizes what an interrupted image retains."""
|
|
trampoline_page = info.base - info.page if info.patch_vector else None
|
|
first = [0, trampoline_page] if info.patch_vector else []
|
|
rest = [a for a in sorted(pages) if a not in first]
|
|
if skip_blank:
|
|
rest = [a for a in rest if pages[a].count(0xFF) != len(pages[a])]
|
|
order = [a for a in first if a in pages] + rest
|
|
if not info.patch_vector:
|
|
order = [a for a in order if a != 0] + ([0] if 0 in pages else [])
|
|
return order
|
|
|
|
|
|
# ----------------------------------------------------------------- fuses ---
|
|
|
|
|
|
# Per-chip boot fuse geometry, keyed by the signature's family/part bytes:
|
|
# which byte of the 'F' reply (low, lock, extended, high) carries BOOTSZ/
|
|
# BOOTRST, and the BOOTSZ->words ladder. A die revision shares its base
|
|
# signature, so one row covers it. The m48s have no boot section and no
|
|
# row — their info block says patch-vector and this table is never
|
|
# consulted. Sources: Atmel-2486/2466/2503 (HIGH fuse), Atmel-2545/8271/
|
|
# DS40002065 (x8: EXTENDED, except the m328s' HIGH), Atmel-8272/8011/2593/
|
|
# 42719 (x4: HIGH).
|
|
_LADDER_128 = {0b11: 128, 0b10: 256, 0b01: 512, 0b00: 1024}
|
|
_LADDER_256 = {0b11: 256, 0b10: 512, 0b01: 1024, 0b00: 2048}
|
|
_LADDER_512 = {0b11: 512, 0b10: 1024, 0b01: 2048, 0b00: 4096}
|
|
BOOT_FUSE = {
|
|
bytes((0x93, 0x07)): (3, _LADDER_128), # m8/8A
|
|
bytes((0x94, 0x03)): (3, _LADDER_128), # m16/16A
|
|
bytes((0x95, 0x02)): (3, _LADDER_256), # m32/32A
|
|
bytes((0x93, 0x0A)): (2, _LADDER_128), # m88/88A
|
|
bytes((0x93, 0x0F)): (2, _LADDER_128), # m88P/88PA
|
|
bytes((0x94, 0x06)): (2, _LADDER_128), # m168/168A
|
|
bytes((0x94, 0x0B)): (2, _LADDER_128), # m168P/168PA
|
|
bytes((0x95, 0x14)): (3, _LADDER_256), # m328
|
|
bytes((0x95, 0x0F)): (3, _LADDER_256), # m328P
|
|
bytes((0x94, 0x0F)): (3, _LADDER_128), # m164A
|
|
bytes((0x94, 0x0A)): (3, _LADDER_128), # m164P/164PA
|
|
bytes((0x95, 0x15)): (3, _LADDER_256), # m324A
|
|
bytes((0x95, 0x08)): (3, _LADDER_256), # m324P
|
|
bytes((0x95, 0x11)): (3, _LADDER_256), # m324PA
|
|
bytes((0x96, 0x09)): (3, _LADDER_512), # m644/644A
|
|
bytes((0x96, 0x0A)): (3, _LADDER_512), # m644P/644PA
|
|
bytes((0x97, 0x06)): (3, _LADDER_512), # m1284
|
|
bytes((0x97, 0x05)): (3, _LADDER_512), # m1284P
|
|
}
|
|
|
|
|
|
def mega_boot(info, fuse_bytes):
|
|
"""Decode a mega's boot configuration from its fuses (the byte and the
|
|
BOOTSZ ladder are per chip): BOOTSZ1:0 in bits 2:1 select the
|
|
boot-section words, BOOTRST in bit 0 (programmed = 0) re-vectors reset
|
|
to its start. Returns (bootrst_programmed, boot_section_start_byte)."""
|
|
entry = BOOT_FUSE.get(bytes(info.signature[1:3]))
|
|
if entry is None:
|
|
raise Error(f"unknown mega signature {info.signature.hex()} — no boot fuse map")
|
|
which, ladder = entry
|
|
fuse = fuse_bytes[which]
|
|
words = ladder[(fuse >> 1) & 0x03]
|
|
return (fuse & 1) == 0, info.flash_size - words * 2
|
|
|
|
|
|
# ---------------------------------------------------------- loader update ---
|
|
|
|
|
|
def image_info(image):
|
|
"""What a pureboot binary says about itself, or None.
|
|
|
|
An update image is a bare slot: nothing about it names the chip it was
|
|
built for, and installing a foreign one bricks the target — so every
|
|
loader carries a stamp for this. Through pureboot 4 the stamp is the
|
|
12-byte info block the device also serves; pureboot 5 serves its identity
|
|
from immediates and carries a 6-byte stamp (magic, version, signature)
|
|
that only this exists for, from which the geometry is looked up exactly as
|
|
it is for a live device.
|
|
|
|
Searched once per known version, so the magic stays three selective bytes
|
|
rather than two that code could carry by chance."""
|
|
for version in range(OLDEST_LOADER, NEWEST_LOADER + 1):
|
|
at = image.find(b"PB" + bytes((version,)))
|
|
if at < 0:
|
|
continue
|
|
if version >= UNIFIED_LOADER:
|
|
if at <= len(image) - 6:
|
|
return Info.from_identity(image[at + 2 : at + 6])
|
|
elif at <= len(image) - 12:
|
|
return Info(image[at : at + 12])
|
|
return None
|
|
|
|
|
|
def loader_image(path):
|
|
"""An update image as the slot's own content: a raw binary already is,
|
|
while a HEX carries the blank below the loader's base, which is peeled off
|
|
here. The base comes from the image's own block, not the device's, so a
|
|
foreign image survives intact for the preflight to reject by name."""
|
|
image = load_image(path)
|
|
embedded = image_info(image)
|
|
if embedded and len(image) > embedded.base:
|
|
image = image[embedded.base :]
|
|
return image
|
|
|
|
|
|
def staging_content(image, info):
|
|
"""The staging slot's content: the image, padding, and — where the
|
|
hand-over jumps through the word below the resident — that word, which for
|
|
a staging copy is its own last one. Composed as an rjmp to the resident,
|
|
so an abandoned staging copy still falls through into a loader."""
|
|
budget = SLOT - 2 if info.patch_vector else SLOT
|
|
if len(image) > budget:
|
|
raise Error(f"loader image is {len(image)} B, the slot holds {budget}")
|
|
content = bytearray(image) + bytearray([0xFF] * (SLOT - len(image)))
|
|
if info.patch_vector:
|
|
through = rjmp_to((info.base - 2) // 2, info.base // 2, info.flash_size // 2)
|
|
content[SLOT - 2], content[SLOT - 1] = through & 0xFF, through >> 8
|
|
return bytes(content)
|
|
|
|
|
|
def update_preflight(image, info, fuse_bytes):
|
|
"""Errors and warnings before any flash is touched. Returns warnings."""
|
|
embedded = image_info(image)
|
|
if embedded is None:
|
|
raise Error(
|
|
"no pureboot info block in the update image — not a pureboot binary, "
|
|
f"or a version this tool ({VERSION}) does not know"
|
|
)
|
|
if embedded.raw[3:] != info.raw[3:]:
|
|
raise Error(
|
|
f"update image is for another target: it declares "
|
|
f"[{embedded.describe()}], the device says [{info.describe()}]"
|
|
)
|
|
warnings = []
|
|
if not info.patch_vector:
|
|
if fuse_bytes is None:
|
|
raise Error("a loader update on this chip needs its fuses — unreadable? pass --assume-fuses")
|
|
bootrst, bls_start = mega_boot(info, fuse_bytes)
|
|
if info.stage < bls_start:
|
|
raise Error(
|
|
f"cannot self-update: the staging slot {info.stage:#06x} lies below the "
|
|
f"boot section ({bls_start:#06x}) where SPM is disabled "
|
|
f"— a boot section of at least two slots ({2 * SLOT} B, BOOTSZ) is "
|
|
f"required, and only an external programmer can change fuses"
|
|
)
|
|
if not bootrst:
|
|
warnings.append(
|
|
"BOOTRST unprogrammed: reset boots the application throughout the update; "
|
|
"an interruption is recovered by re-running this update"
|
|
)
|
|
elif bls_start == info.stage:
|
|
warnings.append(
|
|
"BOOTRST targets the staging slot: brief unrecoverable windows exist while "
|
|
"the staging copy itself is being installed or retired (page-write scale)"
|
|
)
|
|
else:
|
|
warnings.append(
|
|
f"BOOTRST targets {bls_start:#06x}, inside application flash: reset reaches a "
|
|
f"loader only across erased flash from there"
|
|
)
|
|
return warnings
|
|
|
|
|
|
class UpdateState:
|
|
"""The host-side memory of an update in flight: what the staging slot
|
|
held (and page 0, where the update repoints it). Losing this file after
|
|
the staging slot was overwritten loses those saved bytes — the update
|
|
still completes, but the staging region can then only be restored by
|
|
reflashing the application."""
|
|
|
|
def __init__(self, path):
|
|
self.path = path
|
|
self.data = None
|
|
|
|
def load_or_save(self, loader):
|
|
info = loader.info
|
|
if os.path.exists(self.path):
|
|
self.data = json.load(open(self.path))
|
|
if bytes.fromhex(self.data["signature"]) != info.signature or self.data["base"] != info.base:
|
|
raise Error(f"{self.path} belongs to a different device — remove it to start over")
|
|
return
|
|
self.data = {
|
|
"signature": info.signature.hex(),
|
|
"base": info.base,
|
|
"staging": loader.read_flash(info.stage, SLOT).hex(),
|
|
"page0": loader.read_flash(0, info.page).hex() if info.patch_vector else "",
|
|
}
|
|
with open(self.path, "w") as f:
|
|
json.dump(self.data, f)
|
|
|
|
@property
|
|
def staging(self):
|
|
return bytes.fromhex(self.data["staging"])
|
|
|
|
@property
|
|
def page0(self):
|
|
return bytes.fromhex(self.data["page0"])
|
|
|
|
def discard(self):
|
|
os.unlink(self.path)
|
|
|
|
|
|
def write_differing(loader, base, content, order=None, label=None):
|
|
"""Program the pages of `content` at `base` that differ from flash, so a
|
|
resumed phase redoes only what an interruption left."""
|
|
page = loader.info.page
|
|
offsets = list(order) if order is not None else list(range(0, len(content), page))
|
|
written = 0
|
|
with Progress(label, len(offsets)) as bar:
|
|
for offset in offsets:
|
|
want = content[offset : offset + page]
|
|
if loader.read_flash(base + offset, page) != want:
|
|
loader.write_page(base + offset, want)
|
|
written += 1
|
|
bar.step()
|
|
if label:
|
|
verbose(f"{label}: {written} of {len(offsets)} pages differed")
|
|
# The same bounded repair as verify_pages: here a page left wrong is a
|
|
# half-written loader slot.
|
|
for retry in range(RETRIES + 1):
|
|
bad = [
|
|
offset
|
|
for offset in range(0, len(content), page)
|
|
if loader.read_flash(base + offset, len(content[offset : offset + page])) != content[offset : offset + page]
|
|
]
|
|
if not bad:
|
|
break
|
|
if retry == RETRIES:
|
|
raise Error(
|
|
f"verify failed at {base + bad[0]:#06x} after programming "
|
|
f"(still wrong after {RETRIES} retries)"
|
|
)
|
|
for offset in bad:
|
|
verbose(f"rewriting page {base + offset:#06x} (retry {retry + 1})")
|
|
loader.write_page(base + offset, content[offset : offset + page])
|
|
written += 1
|
|
return written
|
|
|
|
|
|
def patch_word0(loader, page0, target_base):
|
|
"""Re-aim word 0 at `target_base` — the resume insurance around
|
|
rewriting a loader slot the reset path goes through."""
|
|
info = loader.info
|
|
patched = bytearray(page0)
|
|
word = rjmp_to(0, target_base // 2, info.flash_size // 2)
|
|
patched[0], patched[1] = word & 0xFF, word >> 8
|
|
write_differing(loader, 0, bytes(patched))
|
|
return bytes(patched)
|
|
|
|
|
|
def op_update_loader(loader, wait, path, state_path, fuse_bytes):
|
|
"""Replace the resident loader with `path`, using the loader as its own
|
|
staging loader. Every phase is idempotent and keyed off the flash state,
|
|
so a re-run resumes; the state file carries what the staging slot held."""
|
|
info = loader.info
|
|
image = loader_image(path)
|
|
for warning in update_preflight(image, info, fuse_bytes):
|
|
print(f"note: {warning}")
|
|
update = image_info(image) # the preflight proved it is there
|
|
verbose(f"installing pureboot {update.version} over pureboot {info.version}")
|
|
staged = staging_content(image, info)
|
|
resident = bytes(image) + bytes([0xFF] * (SLOT - len(image)))
|
|
page = info.page
|
|
|
|
state = UpdateState(state_path)
|
|
if os.path.exists(state_path):
|
|
verbose(f"resuming the update recorded in {state_path}")
|
|
else:
|
|
verbose(f"saving the staging slot to {state_path}")
|
|
state.load_or_save(loader)
|
|
|
|
# A loader already sitting whole in the staging slot IS the staging copy:
|
|
# rewriting it would only meet its own running-slot guard. Any pureboot
|
|
# with the device's info block serves, since a staged copy only streams
|
|
# pages. "Whole" needs both checks — the block where every image carries
|
|
# it and matching byte for byte, and the slot unchanged since this update
|
|
# began, so a half-written install takes the path below instead.
|
|
current = loader.read_flash(info.stage, SLOT)
|
|
# The whole slot is searched: a loader's stamp sits wherever its image put
|
|
# it, which is the end of the code on pureboot 5 and the front of it
|
|
# before that.
|
|
staged_loader = image_info(current)
|
|
if staged_loader is not None and staged_loader.raw == info.raw and current == state.staging:
|
|
print("staging slot already holds a loader — left in place")
|
|
else:
|
|
# Where the staging slot starts at address 0 (the 1 KB tiny13s) its
|
|
# first page carries the reset vector, so it goes last: until then a
|
|
# reset still reaches the old resident.
|
|
order = list(range(0, SLOT, page))
|
|
if info.stage == 0:
|
|
order = order[1:] + [0]
|
|
if write_differing(loader, info.stage, staged, order, label="staging copy"):
|
|
print(f"staging copy installed at {info.stage:#06x}")
|
|
|
|
# Enter it and let it rewrite the resident. Where a patched reset vector
|
|
# routes through the resident, word 0 is re-aimed at the staging copy for
|
|
# the rewrite, so a power loss mid-rewrite still resets into a loader.
|
|
verbose(f"entering the staging copy at {info.stage:#06x}")
|
|
loader.enter_copy(info.stage, wait)
|
|
redirect = info.patch_vector and info.stage != 0
|
|
if redirect:
|
|
verbose("word 0 re-aimed at the staging copy for the rewrite")
|
|
patch_word0(loader, state.page0, info.stage)
|
|
if write_differing(loader, info.base, resident, label="resident"):
|
|
print(f"resident loader rewritten at {info.base:#06x}")
|
|
|
|
# Enter the new resident and put the staging region back: page 0 first
|
|
# where it lives in that region (word 0 then points at the new resident
|
|
# for the rest of the restore), the saved trampoline with the rest.
|
|
verbose(f"entering the new resident at {info.base:#06x}")
|
|
loader.enter_copy(info.base, wait)
|
|
if redirect:
|
|
verbose("word 0 restored")
|
|
write_differing(loader, 0, state.page0)
|
|
order = list(range(0, SLOT, page))
|
|
if info.stage == 0:
|
|
order = [0] + order[1:]
|
|
write_differing(loader, info.stage, state.staging, order, label="staging restore")
|
|
|
|
state.discard()
|
|
print(f"loader updated: pureboot {update.version}, {len(image)} B at {info.base:#06x}, staging region restored")
|
|
|
|
|
|
def check_walk_region(pages, info, fuse_bytes, force):
|
|
"""BOOTRST programmed below the loader means reset reaches it only by
|
|
walking across erased flash; application data in that span would divert
|
|
reset into itself. Needs the fuses (--fuses or --assume-fuses)."""
|
|
if info.patch_vector or fuse_bytes is None:
|
|
return
|
|
bootrst, bls_start = mega_boot(info, fuse_bytes)
|
|
if not bootrst or bls_start >= info.base:
|
|
return
|
|
overlap = [a for a in sorted(pages) if a >= bls_start and pages[a].count(0xFF) != len(pages[a])]
|
|
if overlap and not force:
|
|
raise Error(
|
|
f"the image writes {overlap[0]:#06x}.. inside the reset walk region "
|
|
f"[{bls_start:#06x}, {info.base:#06x}) (BOOTRST programmed): reset could no "
|
|
f"longer reach the loader — --force to flash it anyway"
|
|
)
|
|
|
|
|
|
# ------------------------------------------------------------ operations ---
|
|
|
|
|
|
def op_erase_flash(loader):
|
|
"""0xff over the application area, descending where the reset vector is
|
|
patched: page 0 goes last, so an interrupted erase still resets into the
|
|
loader — and once it is gone, the erased walk reaches it anyway."""
|
|
blank = bytes([0xFF] * loader.info.page)
|
|
addresses = range(0, loader.info.base, loader.info.page)
|
|
with Progress("erase", len(addresses)) as bar:
|
|
for address in reversed(addresses) if loader.info.patch_vector else addresses:
|
|
loader.write_page(address, blank)
|
|
bar.step()
|
|
print(f"erase: {loader.info.base // loader.info.page} pages")
|
|
|
|
|
|
def op_erase_eeprom(loader):
|
|
with Progress("erase EEPROM", loader.info.eeprom_size, "B") as bar:
|
|
loader.write_eeprom(0, bytes([0xFF] * loader.info.eeprom_size), progress=bar)
|
|
print(f"erase: {loader.info.eeprom_size} B of EEPROM")
|
|
|
|
|
|
def op_flash(loader, path, erase, verify, fuse_bytes=None, force=False):
|
|
image = load_image(path)
|
|
verbose(f"{path}: {len(image)} B image")
|
|
pages = plan_flash(image, loader.info)
|
|
check_walk_region(pages, loader.info, fuse_bytes, force)
|
|
if erase:
|
|
op_erase_flash(loader)
|
|
order = covered(pages, loader.info, skip_blank=erase)
|
|
if len(order) != len(pages):
|
|
verbose(f"{len(pages) - len(order)} blank pages skipped (erased flash underneath)")
|
|
with Progress("flash", len(order)) as bar:
|
|
for address in order:
|
|
loader.write_page(address, pages[address])
|
|
bar.step()
|
|
print(f"flash: {path}: {len(order)} pages")
|
|
if verify:
|
|
verify_pages(loader, pages, repair=True)
|
|
|
|
|
|
def verify_pages(loader, pages, repair=False):
|
|
"""Read every page back and compare. With `repair`, a mismatch is
|
|
rewritten and re-read up to RETRIES times first: a page filled over a
|
|
dirty SPM buffer takes stale words, and the write that took them cleared
|
|
the buffer, so one rewrite settles it. Anything still wrong is not that."""
|
|
repaired = 0
|
|
with Progress("verify", len(pages)) as bar:
|
|
for address in sorted(pages):
|
|
for retry in range(RETRIES + 1):
|
|
got = loader.read_flash(address, loader.info.page)
|
|
if got == pages[address]:
|
|
break
|
|
first = next(i for i in range(len(got)) if got[i] != pages[address][i])
|
|
detail = (
|
|
f"verify failed at {address + first:#06x}: "
|
|
f"wrote {pages[address][first]:02x}, read {got[first]:02x}"
|
|
)
|
|
if not repair:
|
|
raise Error(detail)
|
|
if retry == RETRIES:
|
|
raise Error(f"{detail} (still wrong after {RETRIES} retries)")
|
|
verbose(f"{detail} — rewriting page {address:#06x} (retry {retry + 1})")
|
|
loader.write_page(address, pages[address])
|
|
repaired += 1
|
|
bar.step()
|
|
note = f", {repaired} page rewrite(s)" if repaired else ""
|
|
print(f"verify: {len(pages)} pages ok{note}")
|
|
|
|
|
|
def op_verify_flash(loader, path):
|
|
verify_pages(loader, plan_flash(load_image(path), loader.info))
|
|
|
|
|
|
def read_progress(reader, total, label):
|
|
"""A bulk read in 256-byte wire chunks under a progress bar."""
|
|
data = b""
|
|
with Progress(label, total, "B") as bar:
|
|
while len(data) < total:
|
|
chunk = min(256, total - len(data))
|
|
data += reader(len(data), chunk)
|
|
bar.step(chunk)
|
|
return data
|
|
|
|
|
|
def op_read_flash(loader, path):
|
|
data = read_progress(loader.read_flash, loader.info.base, "read flash")
|
|
open(path, "wb").write(data)
|
|
print(f"read flash: {len(data)} B -> {path}")
|
|
|
|
|
|
def op_eeprom(loader, path, erase, verify):
|
|
image = load_image(path)
|
|
if len(image) > loader.info.eeprom_size:
|
|
raise Error(f"EEPROM image is {len(image)} B, device has {loader.info.eeprom_size}")
|
|
if erase:
|
|
op_erase_eeprom(loader)
|
|
with Progress("eeprom", len(image), "B") as bar:
|
|
loader.write_eeprom(0, image, progress=bar)
|
|
print(f"eeprom: {path}: {len(image)} B")
|
|
if verify:
|
|
got = read_progress(loader.read_eeprom, len(image), "verify EEPROM")
|
|
if got != image:
|
|
first = next(i for i in range(len(got)) if got[i] != image[i])
|
|
raise Error(f"verify failed at EEPROM {first:#06x}: wrote {image[first]:02x}, read {got[first]:02x}")
|
|
print(f"verify: {len(image)} B ok")
|
|
|
|
|
|
def op_verify_eeprom(loader, path):
|
|
image = load_image(path)
|
|
got = read_progress(loader.read_eeprom, len(image), "verify EEPROM")
|
|
if got != image:
|
|
first = next(i for i in range(len(got)) if got[i] != image[i])
|
|
raise Error(f"verify failed at EEPROM {first:#06x}: expected {image[first]:02x}, read {got[first]:02x}")
|
|
print(f"verify: {len(image)} B of EEPROM ok")
|
|
|
|
|
|
def op_read_eeprom(loader, path):
|
|
data = read_progress(loader.read_eeprom, loader.info.eeprom_size, "read EEPROM")
|
|
open(path, "wb").write(data)
|
|
print(f"read EEPROM: {len(data)} B -> {path}")
|
|
|
|
|
|
def _require_unified(loader, what):
|
|
if not loader.unified:
|
|
raise Error(f"{what} needs pureboot {UNIFIED_LOADER} or later; this loader is {loader.info.version}")
|
|
|
|
|
|
def _peek_spec(spec):
|
|
"""ADDR[:N] — addresses and counts in any Python integer base."""
|
|
address, _, count = spec.partition(":")
|
|
return int(address, 0), int(count, 0) if count else 1
|
|
|
|
|
|
def op_peek(loader, spec):
|
|
_require_unified(loader, "--peek")
|
|
address, count = _peek_spec(spec)
|
|
data = loader.read_ram(address, count)
|
|
for offset in range(0, len(data), 16):
|
|
row = data[offset : offset + 16]
|
|
text = "".join(chr(b) if 0x20 <= b < 0x7F else "." for b in row)
|
|
print(f"{address + offset:#06x} {row.hex(' '):<47} {text}")
|
|
|
|
|
|
def op_poke(loader, spec):
|
|
_require_unified(loader, "--poke")
|
|
address, _, payload = spec.partition(":")
|
|
if not payload:
|
|
raise Error("--poke needs ADDR:HEX, for example 0x200:deadbeef")
|
|
data = bytes.fromhex(payload.replace(" ", ""))
|
|
loader.write_ram(int(address, 0), data)
|
|
print(f"poke: {len(data)} B at {int(address, 0):#06x}")
|
|
|
|
|
|
def op_fuses(loader):
|
|
low, lock, extended, high = loader.read_fuses()
|
|
print("fuses:")
|
|
print(f" low 0x{low:02x}")
|
|
print(f" high 0x{high:02x}")
|
|
print(f" extended 0x{extended:02x}")
|
|
print(f" lock 0x{lock:02x}")
|
|
fuse_bytes = bytes((low, lock, extended, high))
|
|
# On a boot-sectioned mega the BOOTSZ/BOOTRST decode is the fuse fact the
|
|
# loader's whole deployment hangs on — say it in words.
|
|
if not loader.info.patch_vector:
|
|
try:
|
|
bootrst, bls_start = mega_boot(loader.info, fuse_bytes)
|
|
reset = "reset enters it" if bootrst else "reset boots the application"
|
|
print(f" boot section at {bls_start:#06x} ({loader.info.flash_size - bls_start} B), "
|
|
f"BOOTRST {'programmed' if bootrst else 'unprogrammed'} — {reset}")
|
|
except Error:
|
|
pass # unknown signature: the raw bytes above still stand
|
|
return fuse_bytes
|
|
|
|
|
|
# -------------------------------------------------------------------- cli ---
|
|
|
|
|
|
def main():
|
|
parser = argparse.ArgumentParser(
|
|
description="pureboot host tool", epilog="operations run in the order listed above"
|
|
)
|
|
parser.add_argument("--version", action="version", version=f"%(prog)s {VERSION} "
|
|
f"(speaks pureboot {OLDEST_LOADER}..{NEWEST_LOADER})")
|
|
parser.add_argument("--port", required=True, help="serial device: COM6, /dev/ttyUSB0, or a simavr pty")
|
|
parser.add_argument("--baud", type=int, default=115200, help="115200 mega, 57600 tinies")
|
|
parser.add_argument("--wait", type=float, default=30.0, help="seconds to keep knocking")
|
|
parser.add_argument("--autobaud", action="store_true",
|
|
help="drive an autobaud loader: send the 0xC0 calibration pulse and a single "
|
|
"knock, and take geometry from the signature (no clock/baud baked in)")
|
|
parser.add_argument("--info", action="store_true", help="print the device info block")
|
|
parser.add_argument("--fuses", action="store_true", help="read the fuse and lock bytes")
|
|
parser.add_argument("--update-loader", metavar="FILE", help="replace the loader with this pureboot binary")
|
|
parser.add_argument("--state", metavar="FILE", help="update state file (default: FILE.pbstate)")
|
|
parser.add_argument("--assume-fuses", metavar="HEX8", help="fuse bytes low,lock,ext,high as 8 hex digits "
|
|
"(overrides reading them — e.g. under a simulator that cannot)")
|
|
parser.add_argument("--erase-flash", action="store_true", help="0xff over the application flash")
|
|
parser.add_argument("--flash", metavar="FILE", help="program an application (bin or ihex)")
|
|
parser.add_argument("--no-verify", action="store_true", help="skip read-back after writes")
|
|
parser.add_argument("--read-flash", metavar="FILE", help="dump the application flash")
|
|
parser.add_argument("--verify-flash", metavar="FILE", help="compare flash against an image")
|
|
parser.add_argument("--erase-eeprom", action="store_true", help="0xff over the EEPROM")
|
|
parser.add_argument("--eeprom", metavar="FILE", help="program the EEPROM (bin or ihex)")
|
|
parser.add_argument("--read-eeprom", metavar="FILE", help="dump the EEPROM")
|
|
parser.add_argument("--verify-eeprom", metavar="FILE", help="compare EEPROM against an image")
|
|
parser.add_argument("--peek", metavar="ADDR[:N]", help="read N bytes of data space (SRAM, registers, "
|
|
"I/O) — pureboot 5 and later")
|
|
parser.add_argument("--poke", metavar="ADDR:HEX", help="write hex bytes into data space — "
|
|
"pureboot 5 and later")
|
|
parser.add_argument("--force", action="store_true", help="override refusable safety checks")
|
|
parser.add_argument("--stay", action="store_true", help="leave the loader in its session")
|
|
parser.add_argument("-v", "--verbose", action="store_true",
|
|
help="print decisions and derived facts as operations run")
|
|
args = parser.parse_args()
|
|
global VERBOSE
|
|
VERBOSE = args.verbose
|
|
|
|
if args.update_loader and (args.flash or args.erase_flash):
|
|
parser.error("--update-loader does not combine with application flash operations")
|
|
fuse_override = None
|
|
if args.assume_fuses:
|
|
try:
|
|
fuse_override = bytes.fromhex(args.assume_fuses)
|
|
assert len(fuse_override) == 4
|
|
except (ValueError, AssertionError):
|
|
parser.error("--assume-fuses takes 8 hex digits: low,lock,extended,high")
|
|
|
|
port = Port(args.port, args.baud)
|
|
verbose(f"{args.port}: {args.baud} Bd 8N1, DTR/RTS asserted")
|
|
try:
|
|
loader = Loader(port)
|
|
info = loader.connect_autobaud(args.wait) if args.autobaud else loader.connect(args.wait)
|
|
if args.info:
|
|
print("device:")
|
|
for line in info.lines():
|
|
print(f" {line}")
|
|
fuse_bytes = fuse_override
|
|
if args.fuses or (args.update_loader and not info.patch_vector and fuse_bytes is None):
|
|
read = op_fuses(loader)
|
|
if fuse_bytes is None:
|
|
fuse_bytes = read
|
|
if args.update_loader:
|
|
state = args.state or args.update_loader + ".pbstate"
|
|
op_update_loader(loader, args.wait, args.update_loader, state, fuse_bytes)
|
|
if args.flash:
|
|
op_flash(loader, args.flash, args.erase_flash, not args.no_verify, fuse_bytes, args.force)
|
|
elif args.erase_flash:
|
|
op_erase_flash(loader)
|
|
if args.read_flash:
|
|
op_read_flash(loader, args.read_flash)
|
|
if args.verify_flash:
|
|
op_verify_flash(loader, args.verify_flash)
|
|
if args.eeprom:
|
|
op_eeprom(loader, args.eeprom, args.erase_eeprom, not args.no_verify)
|
|
elif args.erase_eeprom:
|
|
op_erase_eeprom(loader)
|
|
if args.read_eeprom:
|
|
op_read_eeprom(loader, args.read_eeprom)
|
|
if args.verify_eeprom:
|
|
op_verify_eeprom(loader, args.verify_eeprom)
|
|
if args.poke:
|
|
op_poke(loader, args.poke)
|
|
if args.peek:
|
|
op_peek(loader, args.peek)
|
|
if args.stay:
|
|
print("loader stays in its session (reset to leave)")
|
|
else:
|
|
loader.run_application()
|
|
print("application running")
|
|
finally:
|
|
port.close()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
try:
|
|
main()
|
|
except Error as error:
|
|
print(f"error: {error}", file=sys.stderr)
|
|
sys.exit(1)
|
|
except KeyboardInterrupt:
|
|
sys.exit(130)
|