A31

Allwinner A31 (sun6i) SoC features a Quad-Core Cortex-A7 ARM Processor SoC, and a Power VR SGX544 (with 8 shader engines) GPU from Imagination Technologies.

=Overview= A31 powered by 4 CPU and 8 GPU (Power VR SGX544 for Ployer and Power VR SGX544MP2 for Onda).

A31 CPU architecture consists of quad ARM Cortex-A7 cores to deliver decent computing capability while consuming less power, and integrates the PowerVR SGX544 GPU. It also features Cedar Engine multimedia processing unit that is capable of up to 2160p (3840x1080@30fps 4k resolution or 1080p 3D decoding) video decoding, with integrated HDMI 1.4 output support, and H.264 HP (High Profile) in 1080p at 30fps video encoding.

Proper Linux support now difficult for A31 due to the Power VR GPU, though; however, its kernel source is available now and also for U-boot.

Cortex-A7
Cortex-A7 is 100% ISA compatible with the Cortex-A15, this includes the new virtualization instructions, integer divide support and 40-bit memory addressing. Any code running on an A15 can run on a Cortex A7, just slower. This is a very important feature as it enables SoC vendors to build chips with both Cortex A7 and Cortex A15 cores, switching between them depending on workload requirements. ARM calls this a big.LITTLE configuration.

A31s
The A31s is the same die as the A31 in a different package. In terms of hardware specification and functionality they are identical.

=A31 SoC Features=
 * CPU:
 * ARM Cortex-A7 Quad-Core (revision r0p3)
 * 256KB L1-Cache
 * 1MB L2-Cache
 * GPU:
 * Power VR SGX 544
 * Eight logic cores (8 shader engines)
 * Comply with Open GL ES2.0, Open CL1.x, DX 9_3
 * Video:
 * UHD H.264 4K ×2K @30fps video decoding
 * Full HD video decoding
 * BD Directory, BD ISO and BD m2ts video decoding
 * H.264 High Profile 1080P@60fps encoding
 * 3840x1080@30fps 3D decoding
 * Comply with RTSP, HTTP, HLS, RTMP, MMS streaming media protocol
 * Display:
 * Dual-Channel LVDS 1920 ×1080@60fps
 * 4-lane MIPI DSI 1920 × 1200@ 60fps
 * Dual-Channel RGB/CPU 2048 ×1536@60fps
 * Integrated HDMI 1.4 4K ×2K@ 30fps
 * Camera:
 * Integrated Parallel & MIPI I/F sensor
 * Integrated Powerful ISP, supporting Raw Data CMOS sensor
 * 5M/8M/12M CMOS Sensor supported
 * 8/10/12-bit RGB Bayer sensor supported
 * Memory:
 * Dual-Channel LPDDR2/DDR3/DDR3L Controller
 * Dual-Channel NAND FLASH Controller
 * 64-bit ECC
 * PMIC:
 * A31exclusively tailor-made PMIC AXP221
 * 21-CH power output and 2.2A Flash charging
 * Comply with USB 3.0 power supply standard
 * Embedded Controller:
 * AR100, an OpenRISC controller. Manages deep powersave modes.
 * Audio:
 * Integrated HI-FI 100dB Audio Codec
 * Three MIC
 * One MIC with Noise cancellation
 * OS:
 * Support Android 4.2 or up
 * Support Microsoft Windows 8

=History= The A31 was initially rumored to be called the A40 instead. On July 9 cnbeta.com and chinaeshops speculated that the next SoC from Allwinner will be a Quad-Core Cortex-A7 ARM Processor SoC, and twice as many GPU cores as it has CPU cores, (it was also unclear early on which GPU it would had, and rumors speculated on Mali 450, Mali T604, or Mali T658 GPU).

"This new SoC was thus most likely be either called Allwinner A40 if the pictures from iLife Tech banners taken at Hong Kong Electronics Fair 13-16 October 2012 are correct".

"It's look like Veda confirm the rumor with a tablet, Veda X75, which include an A40 (Quad-Core / 8GPU)".

Onda V972, a 10-inch Android tablet, was the first device to be publicly announced to come with an Allwinner A31 SoC.

= Documentation =


 * A31 Datasheet v1.50 (PDF, 42 pages 2015-03-20)
 * A31 User Manual v1.30 (PDF, 1064 pages 2015-04-15)
 * A31 Datasheet v1.30 (PDF, 42 pages, 2013-11-06)
 * A31 User Manual v1.10 (PDF, 1050 pages, 2013-06-30)
 * A31 Datasheet v1.00 (PDF, 43 pages, 2012-11-06)
 * A31 Brief v1.1 (PDF, 3 pages)

= Software =

Original SDKs
We have made some SDKs available on our server:
 * a31_V4.5_MerriiLinux_Humming (Full, Reduced, Unpacked)
 * a31_hummbingbird_V3.3_v2_kfb_0k (Full, Reduced, Unpacked)
 * a31_v4.5_hummingbird_kfb_ok (Full, Reduced, Unpacked)

GPL Violations
The publically available SDKs contain kernel and u-boot trees which include and depend on several binaries. Allwinner is violating the GPL quite directly here.

kernel

 * drivers/input/touchscreen/libAW5306
 * drivers/media/video/sunxi-vfe/lib/libisp
 * modules/nand_v2/libnand

u-boot

 * nand_sunxi/libnand

kernel

 * drivers/input/touchscreen/libAW5306
 * drivers/media/video/sunxi-vfe/lib/libisp
 * modules/nand/libnand
 * modules/nand_v2/libnand

u-boot

 * nand_sunxi/sun7iw1/libnand-sun7iw1
 * nand_sunxi/sun8iw1/libnand-sun8iw1
 * nand_sunxi/sun8iw3/libnand-sun8iw3
 * nand_sunxi/sun9iw1/libnand-sun9iw1

kernel

 * drivers/media/video/sunxi-vfe/lib/libisp
 * modules/nand_v2/libnand

AW5306 code does seem to be available in this release, which reveals that this is Awinic code

u-boot

 * nand_sunxi/sun7iw1/libnand-sun7iw1
 * nand_sunxi/sun8iw1/libnand-sun8iw1
 * nand_sunxi/sun8iw3/libnand-sun8iw3
 * nand_sunxi/sun9iw1/libnand-sun9iw1

= Devices = = See also =
 * A10
 * A10s
 * A13
 * A20
 * A23
 * A31 EVB
 * A33
 * Power VR

=Owners of the SoC on IRC= bamvor, ojn, drachensun or mripard own an A31-based board.

=Community Support= There is no support for the A31 and the A31s in u-boot-sunxi and in the linux-sunxi 3.4 kernel, but both mainline u-boot and the mainline Linux kernel have basic support for the A31 and A31s (cf. the respective links for further information).

=References=

= External links =
 * Product Page
 * A31 PCB - tablet tear down
 * Allwinner A31 Brief
 * Allwinner A31 Block Diagram
 * A31 Supported DDR list
 * A31 Supported NAND list
 * A31 Supported LCD modules list
 * A31 Supported Capacitive touch sensor list
 * A31 Supported Camera devices list
 * Allwinner A31 kernel source code
 * Allwinner A31 U-boot source code