Supported devices

Every board rpi-hal runs on, and how complete its support is. The README has the status of each driver.

An application selects the chip with exactly one cargo feature. None is a default, because there is no sensible default chip:

Chip feature	Chip	Boards	Targets
bcm2837	BCM2836, BCM2837	Pi 2, Pi 3	armv7a-none-eabi, aarch64-unknown-none-softfloat
bcm2711	BCM2711	Pi 4	armv7a-none-eabi, aarch64-unknown-none-softfloat
bcm2835	BCM2835	Pi 1, Pi Zero, Pi Zero W	armv6-none-eabi (nightly)

Pi 2 and Pi 3

BCM2836 (Pi 2 Model B rev 1.1, Cortex-A7) and BCM2837 (Pi 2 rev 1.2 and Pi 3, Cortex-A53). The main targets, where rpi-hal’s drivers are developed first.

The Pi 2 rev 1.1’s Cortex-A7 cores are 32-bit only, so that board runs armv7a-none-eabi builds alone. The Pi 3 runs either.

Pi 4

BCM2711, Cortex-A72. Preliminary. The bcm2711 feature selects the relocated peripheral memory map and PAC. Working, in both 32-bit and 64-bit builds:

• boot, GPIO and the System Timer;
• the MMU identity map and mailbox coherency;
• the UART console;
• the SD card, through the BCM2711-specific EMMC2 controller, and so the loader’s card commands.

Most other drivers are untested here, and there is no interrupt controller (GIC-400) support yet, so nothing interrupt-driven runs, Embassy included. Issue #29 tracks the bring-up.

Pi 1 and Pi Zero

BCM2835, ARM1176JZF-S. Preliminary. The bcm2835 feature selects the chip’s peripheral map and PAC. Building for armv6-none-eabi selects the ARMv6 boot code, barriers and MMU programming. Working, on a Pi Zero W:

• boot and GPIO;
• the UART console;
• the System Timer;
• the MMU with the data and instruction caches on, including the exclusive monitor that atomics rely on.

Interrupts and the drivers above the SoC basics are untested.

Three features don’t exist on this chip at all, rather than being untested: multicore (it has one core), and generic_timer and pmu, which rest on ARMv7-only CPU state or on the ARM-local peripheral block the BCM2835 doesn’t have.

armv6-none-eabi is a tier-3 target with no precompiled core, so this board needs nightly Rust and -Z build-std. A project from Start a project is set up for it already.

Planned

• Pi Zero 2 W (RP3A0, the Pi 3’s BCM2837 in a smaller package).
• Pi 5 (BCM2712, with most of its I/O moved onto the separate RP1 chip).

Neither runs rpi-hal yet.