arm-trusted-firmware VS coreboot

I have a PinePhone Pro, and I'm trying to figure out a reasonable way to get more than one half of ten minutes of battery life out of it, while still receiving notifications. I figure the best route to go will be to create a service that holds ports open, while the CPU is completely asleep, and either run it on the modem's processor or, as an possibility for the PinePhone Pro, but not the original Pinephone, run it on the m0 core used for power management.

Arm v7 was a Wild West, but with v8, Arm tried to standardize a lot. The Arm Trusted Firmware is the reference boot firmware implementation for v8+ CPUs: https://github.com/ARM-software/arm-trusted-firmware.

I'd think most of the referece documents can be discovered from that code base.

Relatedly, from the perspective of hands-on programming, the System Programmer's guide is the manual to start with.

I assure you that there is no lack of skill; that is just what happens over the course of ten years in a 300,000 line code-base and multiple hundreds of contributors: https://github.com/ARM-software/arm-trusted-firmware/blob/master/Makefile

The ARM Trusted Firmware is what typically runs in the secure world, and it is indeed open source: https://github.com/ARM-software/arm-trusted-firmware

ROM code generally speaking is not open source, but has been dumped on occasion.

The reference Trustzone implementation for ARM is open source https://github.com/ARM-software/arm-trusted-firmware , so I really can't think of some reason the ARM license would have to do with it.

SMP support (at least as far as CPU suspend and hotplug goes) is usually handled by TrustZone firmware on aarch64, not by the kernel (see PSCI). If you write your own OS on a bare-metal platform you can of course do what you want, but if you're looking for existing sources that's where you'd have to look. https://github.com/ARM-software/arm-trusted-firmware is a common reference implementation that supports a bunch of platforms, but many others (e.g. all Samsung and Qualcomm phones) also use their own proprietary stuff which is not publicly available.

Come again? https://github.com/ARM-software/arm-trusted-firmware

Why BIOS (did you mean UEFI?) when it runs the best boot loader, which is Coreboot¹. Many users would love to re-flash their bios/uefi for it, if it’s supported.

1: https://www.coreboot.org/

Coreboot is 0.6% C++.

NovaCustom ; some models come with Dasharo a coreboot distribution.

You can also use Mr. Chromebox Script to install Coreboot on your chromebook to get a UEFI BIOS on your Chromebook and then you can go an install either a linux distro or even Windows if you want. It's a pretty straightforward process and also reversable if you want to go back to just using ChromeOS.

Some models are available with Dasharo a [coreboot]https://www.coreboot.org/) distribution.

why no haswell_ult_dmi_registers for broadwell? in https://github.com/coreboot/coreboot/blob/master/util/inteltool/pcie.c

use croshfirmware.sh from https://github.com/coreboot/coreboot/tree/master/util/chromeos

There may be other protections to restrict SPI flash access for security reasons (so you might not be able to flash your custom firmware in the OS), but worst case you can use a HW flasher (or maybe USB flashback). Still, this doesn't address the elephant in the room - platform initialization code might be open-sourced, but that isn't everything. You'll still need to figure out the board-specific stuff (the Super I/O chip, chipset GPIOs, other peripherals, etc.). Using coreboot as an example, Intel provides the Firmware Support Package blob to handle platform initialization. I think AGESA is somewhat similar to this, though Intel publicly releases the binaries for use in coreboot/etc. Thanks to the FSP, coreboot has support for recent Intel chipsets. However, there is only support for two recent consumer boards: the MSI PRO Z690-A WiFi DDR4 and DDR5.

does anyone know what is https://github.com/coreboot/coreboot/blob/b12caef23bc1b29c2e658f2b728cc4beac1e62b9/src/northbridge/intel/haswell/vcu_mailbox.c

Download crosfirmware.sh and run it from command line: bash crosfirmware.sh droid