4.4. Microchip (Atmel) AT91¶
The Microchip (former Atmel) AT91 architecure has very good support within barebox. Most boards today have their description in their board files, but boards are slowly migrating to use DT. Likewise most boards are not yet migrated to multi image support, but this is also ongoing.
The boot process of the AT91 CPU’s is a two step process. The first step is named the bootstrap and at91bootstrap is often used (https://github.com/linux4sam/at91bootstrap). barebox supports bootstrapping some at91 boards as documented in the following.
The bootstrap program are loaded by a boot program and can be loaded from DataFlash, NAND Flash, SD Card or via USB. The bootstrap program do the low-level configuration of the processor and then load and execute barebox.
4.4.1. AT91 boards¶
Newer boards can be built with the
make ARCH=arm at91_multi_defconfig
The resulting images will be placed under
barebox-at91sam9x5ek.img barebox-at91sam9263ek.img barebox-microchip-ksz9477-evb.img barebox-microchip-ksz9477-evb-xload-mmc.img barebox-sama5d3-xplained.img barebox-sama5d3-xplained-xload-mmc.img barebox-sama5d27-som1-ek.img barebox-sama5d27-som1-ek-xload-mmc.img barebox-groboards-sama5d27-giantboard.img barebox-groboards-sama5d27-giantboard-xload-mmc.img barebox-skov-arm9cpu.img
Older supported boards have yet to be migrated to multi-image and device tree. The majority of these have a short entry here. For each board defconfig file(s) are noted but barebox may include additional defconfig files and may also include boards not included in the following.
- 220.127.116.11. Atmel AT91RM9200-EK Evaluation Kit
- 18.104.22.168. Atmel AT91SAM9260-EK Evaluation Kit
- 22.214.171.124. Atmel AT91SAM9261-EK Evaluation Kit
- 126.96.36.199. Atmel AT91SAM9263-EK Evaluation Kit
- 188.8.131.52. Atmel AT91SAM9G10-EK Evaluation Kit
- 184.108.40.206. Atmel AT91SAM9G20-EK Evaluation Kit
- 220.127.116.11. Atmel AT91SAM9M10G45-EK Evaluation Kit
- 18.104.22.168. Atmel AT91SAM9N12-EK Evaluation Kit
- 22.214.171.124. Atmel AT91SAM9X5-EK Evaluation Kit
- 126.96.36.199. Atmel SAMA5D3X Evaluation Kit
- 188.8.131.52. Atmel SAMA5D4 XPLAINED ULTRA Evaluation Kit
- 184.108.40.206. Somfy Animeo IP
- 220.127.116.11. Atmel Telit EVK-PRO3
This is a list of AT91 specific TODO items, listed in no particular order.
Update remaining boards to DT
Update remaing boards to support multi image boot
Introduce defaultenv2 for all boards
Add pwm driver (required to support backlight)