| .. SPDX-License-Identifier: GPL-2.0+ |
| |
| U-Boot for Apple Silicon Macs |
| ============================= |
| |
| Allows Apple Silicon Macs to boot U-Boot via the m1n1 bootloader |
| developed by the Asahi Linux project. At this point the machines with |
| the following SoCs work: |
| |
| - Apple M1 SoC (t8103) |
| - Apple M1 Pro SoC (t6000) |
| - Apple M1 Max SoC (t6001) |
| - Apple M1 Ultra SoC (t6002) |
| |
| On these SoCs the following hardware is supported: |
| |
| - S5L serial port |
| - SPI keyboard (on laptops) |
| - Framebuffer |
| - NVMe storage |
| - USB 3.1 Type-C ports |
| |
| Device trees are currently provided for the M1 Mac mini (2020, J274), |
| M1 MacBook Pro 13" (2020, J293), M1 MacBook Air (2020, J313) and M1 |
| iMac (2021, J456/J457). |
| |
| Building U-Boot |
| --------------- |
| |
| .. code-block:: bash |
| |
| $ export CROSS_COMPILE=aarch64-none-elf- |
| $ make apple_m1_defconfig |
| $ make |
| |
| This will build ``u-boot-nodtb.bin`` as well as devices trees for some |
| of the supported machines. These device trees can be found in the |
| ``arch/arm/dts`` subdirectory of your build. |
| |
| Image creation |
| -------------- |
| |
| In order to run U-Boot on an Apple Silicon Mac, U-Boot has to be used |
| as a payload for the m1n1 bootloader. Instructions for building m1n1 |
| can be found here: |
| |
| https://github.com/AsahiLinux/docs/wiki/SW%3Am1n1 |
| |
| .. code-block:: bash |
| |
| $ cat m1n1.macho t8103-j274.dtb u-boot-nodtb.bin > u-boot.macho |
| |
| This uses ``u-boot-nodtb.bin`` as the device tree is passed to U-Boot |
| by m1n1 after making some adjustments. |
| |
| Image installation |
| ------------------ |
| |
| Instructions on how to install U-Boot on your Mac can be found at: |
| |
| https://github.com/AsahiLinux/docs/wiki/Developer-Quickstart |
| |
| Just replace ``m1n1.macho`` with ``u-boot.macho`` in the instructions. |
| |
| Debug UART |
| ---------- |
| |
| Since the base address of the UART is SoC-dependent, the debug UART is |
| not enabled by default. To enable the debug UART the base address |
| needs to be adjusted and the CONFIG_DEBUG_UART option needs to be |
| enabled. The table below gives the correct base address for the |
| supported SoCs. |
| |
| .. list-table:: |
| :widths: 32 16 |
| :header-rows: 1 |
| |
| * - SoC |
| - Base Address |
| * - M1 (t8103) |
| - 0x235200000 |
| * - M1 Pro/Max/Ultra (t6000/t6001/t6002) |
| - 0x39b200000 |
