rpi-loader 0.4.0

Added

• rpi-loader completions [shell], writing a shell completion script
  to stdout — bash unless another is named, with zsh, fish, elvish and
  powershell also available. Each release also carries a ready-made
  rpi-loader-<version>.bash, for installing it without building the CLI
  first.

  Generated from the same Command clap builds for --help, so it
  describes the CLI that is actually compiled. That is why it is a
  subcommand rather than a build script: a build script cannot see the
  Cli type without moving it into a library, and a checked-in script
  goes stale the first time a flag is renamed.

  Printed rather than written to a path this picks, because where a
  completion belongs differs by shell, distribution and whether the user
  can write outside their home. The subcommand's --help gives the two
  usual destinations.

  The bash script completes --device to the serial ports actually
  attached, by asking rpi-loader list when Tab is pressed. clap knows
  only that the flag takes a string, which its generator turns into
  filename completion over the whole machine; which ports exist is a
  runtime fact that no generated script can hold. A small wrapper around
  clap's own function does it, so everything else completes exactly as
  generated, and it is bash-only — the other shells get clap's script
  untouched.

  The bash script also carries a workaround for a clap_complete bug that
  makes every subcommand's completion silently empty when the binary's
  name contains a hyphen — which this one does. Its generator writes each
  case label twice and mangles the name differently each time: the
  dispatcher sets cmd="rpi__loader__subcmd__boot" while the arm holding
  that subcommand's options is spelled rpi__subcmd__loader__subcmd__boot,
  so no arm is ever reachable and nothing past the first word completes.
  tests/completions.rs checks the invariant rather than the instance —
  every label the dispatcher can set must exist as an arm — so a future
  desync fails a test whether or not it is this one.

  Deliberately not clap_complete's dynamic engine, which would do this
  for every argument at once: it is behind two unstable feature flags
  (clap_complete/unstable-dynamic and clap/unstable-ext), which in a
  crate installed with cargo install means someone else's install
  breaking on a dependency bump — and the script it registers embeds the
  absolute path of the binary that generated it, so it could not be the
  file shipped with a release.

• Pi 1 / Pi Zero (BCM2835) support. src/boot6.s is the ARMv6
  counterpart to the existing relocating boot stub: the same copy to
  0x00200000 and jump, without the core-id check (MPIDR is an ARMv7
  register, and this chip has one core) and with the two barriers as the
  CP15 operations ARMv6 has instead of dsb/isb — the same substitution
  exec now makes. make build-bcm2835 produces firmware/target/ kernel.img, on the armv6-none-eabi target, and is the one recipe here
  that needs nightly: that target is tier 3, so -Z build-std has to
  compile core for it.

  The chip is now a feature of this package (bcm2837 by default,
  forwarding to rpi-hal's) rather than a hardcoded entry on the rpi-hal
  dependency line. It has to be: rpi-hal prefers bcm2837 over
  bcm2835 when both are enabled, so a Pi Zero build that could not turn
  bcm2837 off would have silently compiled the Pi 3's peripheral base
  into a Pi Zero image. Existing invocations are unaffected — a plain
  build is still the Pi 2/3 one, and --features bcm2711 still the Pi 4
  one.

  The rpi-hal floor moves to 0.6.0, which is where the bcm2835
  feature arrived.

Images

Copy the image matching your board to the SD card's boot
partition, renamed to the filename in its own name:
kernel7.img (32-bit), kernel8.img (64-bit) or kernel.img
(ARMv6). The firmware loads one of those names and no others,
chosen by the CPU it finds, and a board handed the wrong one
stops without printing anything. Use kernel8.img only with
arm_64bit=1 in config.txt.

bcm2837 covers the Pi 2 v1.2 and Pi 3; bcm2711 covers the
Pi 4; bcm2835 covers the Pi 1 and Pi Zero, and is ARMv6, so it
has no 64-bit counterpart. Verify with
sha256sum -c SHA256SUMS.

rpi-loader-<version>.bash is the bash completion for the host
CLI, for installing without building it first:

sudo cp rpi-loader-<version>.bash \
  /usr/share/bash-completion/completions/rpi-loader

The host CLI is a separate install: cargo install rpi-loader.