[[!meta title="NetBSD/evbarm on Allwinner Technology SoCs"]]

[[!toc levels=2]]

# Supported boards
 - [Banana Pi](http://www.bananapi.org/p/product.html) (BPI)
 - Cubieboard 2 (CUBIEBOARD)
 - Cubietruck (CUBIETRUCK)
 - [Merrii Hummingbird A31](http://www.merrii.com/en/pla_d.asp?id=172) (HUMMINGBIRD_A31)

# Supported hardware
 - SoCs
   - Cortex-A7: A20 (2-core), A31 (4-core)
 - SD/MMC controller (DMA)
 - DMA controller
 - GPIO
   - Configuration using FEX scripts is supported
 - UART
 - I2C
 - P2WI (A31)
 - PMU
   - AXP209 (A20)
   - AXP221 (A31)
 - Watchdog timer
 - RTC
 - Audio codec
 - USB host
   - OHCI
   - EHCI
   - OTG (not yet working on A31)
 - SATA (A10/A20)
 - Gigabit Ethernet (GMAC)
 - HDMI (A20/A31)
   - DDC / EDID mode detection
   - Audio support
 - Framebuffer
 - IR receiver (A20/A31)

# TODO
 - SoCs
   - Cortex-A8: A10
   - Cortex-A7/A15: A80
 - OTG (A31)
 - USB device mode
 - Bluetooth / WiFi (Cubietruck, Hummingbird A31)
 - 3G (Hummingbird A31)
 - SD/MMC UHS-I support (needs sdmmc(4) changes)
 - TV input (Hummingbird A31)
 - NAND
 - Fast Ethernet (EMAC)
 - IR transmitter (A20)

# Installation

## A10 / A20 / A31 based boards

* Start with an ARMv7 image from *evbarm-earmv7hf/binary/gzimg/* such as *beagleboard.img*
* Download a U-Boot build for your board
  * A10/A20: Download from the linux-sunxi web site <http://dl.linux-sunxi.org/nightly/u-boot-sunxi/u-boot-sunxi/u-boot-sunxi-latest/>
  * A31: The standard u-boot-sunxi tree doesn't support A31 yet. Until sun6i support is merged, a build is available at <http://dis.invisible.ca/allwinner/a31/> 
* Write the *u-boot-sunxi-with-spl.bin* loader to the base image:
[[!template  id=programlisting text="""
# dd if=u-boot-sunxi-with-spl.bin of=beagleboard.img bs=1k seek=8 conv=notrunc
"""]]
* Write the image to an SD card.
* Copy the kernel (netbsd.ub) for your board to the root of the MS-DOS partition.
* Create or edit uEnv.txt on the MS-DOS partition:
[[!template  id=programlisting text="""
bootargs=root=ld0a
uenvcmd=mmc dev 0; mmc rescan; fatload mmc 0:1 82000000 netbsd.ub; bootm 82000000
"""]]

# Big (endian) fun

You can run this boards with a little endian (this is the default and implied by above install instructions)
or with a big endian kernel and userland. However, kernel and userland endianness needs to match.

To build a big endian release (or sets) use 
[[!template  id=programlisting text="""
./build.sh -m evbearmv7hf-eb 
"""]]
where -eb means endianness big, hf is hardware floating point support, and earm is the modern "extended" ABI for ARM CPUs, and finally v7 is version 7 of the supported instruction set.

# FEX scripts

Board configuration scripts can be found here: <https://github.com/linux-sunxi/sunxi-boards/blob/master/sys_config>. You can compile them with the "fex2bin" tool found here: <https://github.com/linux-sunxi/sunxi-tools>.

To use, copy the compiled FEX to your MS-DOS partition, load it with U-Boot, and then tell the kernel where to find it with the "sysconfig=" boot option. For example, uEnv.txt on a Cubieboard2 might look like this:

[[!template  id=programlisting text="""
bootargs=root=ld0a sysconfig=0x43000000
uenvcmd=mmc dev 0; mmc rescan; fatload mmc 0:1 43000000 cubieboard2.bin; fatload mmc 0:1 82000000 netbsd.ub; bootm 82000000
"""]]

Some pre-compiled .bin files can be found here: <http://ftp.netbsd.org/pub/NetBSD/misc/jmcneill/allwinner/fex/>

# Framebuffer console

To use HDMI for the console device, add *console=fb* to bootargs in uEnv.txt.

If the connected display does not let you disable overscan, you can add a margin to the framebuffer by with the *fb.margin* bootargs option. For example, to set a 25-pixel margin around the screen, add *fb.margin=25* to uEnv.txt

# HDMI audio

The default audio device is the analog audio codec. To change the default device, use the *audiocfg* command:

[[!template  id=programlisting text="""
a31# audiocfg list
0: [*] audio0 @ awinac0: Allwinner CODEC A31, 2 playback channels
1: [ ] audio1 @ awinhdmiaudio0: Allwinner HDMI 1.4, 2 playback channels
a31# audiocfg default 1
setting default audio device to audio1
a31# audiocfg list
0: [ ] audio0 @ awinac0: Allwinner CODEC A31, 2 playback channels
1: [*] audio1 @ awinhdmiaudio0: Allwinner HDMI 1.4, 2 playback channels
"""]]

# Board specific notes

## Merrii Hummingbird A31

There doesn't appear to be a meaningful way to generate a MAC address on these boards. U-Boot from the A31 SDK and from the u-boot-sunxi tree both lack GMAC support, and the Security ID registers (at 0x01c23800) appear to be empty.

To overcome this, you can specify your own MAC address in *uEnv.txt*:
[[!template  id=programlisting text="""
bootargs=root=ld0a awge0.mac-address=02:a0:3d:88:1a:1e
"""]]