This is intended to be a repository for info on the MStar/SigmaStar SoCs. The name is a parody of linux-sunxi for Allwinner SoCs. MStar in Chinese is chenxing and the newer SigmaStar name is xingchen.
This will probably never get as big as linux-sunxi so github pages should be more than enough.
Before MStar was bought out by MediaTek the company offered a wide range of SoCs focused at STB and camera applications. Since the company was bought by MediaTek the camera SoC part of the company has been spun out into the fully owned subsidiary called Sigmastar. The camera SoCs that are now marketed by Sigmastar will be the main focus here.
It’s worth noting that the MStar/Sigmastar camera SoCs seem to be derived from the SoCs made by Alpha Imaging Technology which was merged into MStar at some point.
|load u-boot SPL from vendor IPL||load u-boot from SPI NOR|
|boots to shell from initramfs||boots to shell from local storage||full system from local storage with network etc||boots without blobs (no vendor IPL)|
This table is an attempt to collect all of the different part numbers for the different families and the resources that have been found to reverse engineer each of them.
If possible the data codes will have the earliest known date code so that we can tell roughly when each type of chip was produced.
|family||part||date codes||sample device acquired||boot rom dumped||firmware dumped||SDK acquired||product brief acquired||datasheet acquired|
|msc316dc||1929S||yes||same as msc313e||yes||yes|
MStar used to make a lot of MIPS based SoCs for STBs. These aren’t that interesting in themselves but the IP blocks used in the MIPS SoCs were carried forward to the later ARM chips so any datasheets that can be found for the MIPS SoCs might help with reverse engineering the current ARM based ones.
references to infinity2m in SDK. seems to be a multi-core part.
SSD202 - Dual Cortex A7 with 128MB of DDR3 in a QFN128
Doesn’t seem to exist.
According to the code that is in the wild and SigmaStars page there are some Cortex-A53 based chips.
Injoinic seem to be the recommended PMIC vendor for these chips. Maybe like the Allwinner/Xpowers relationship?
To get the device tree out of the kernel you can use binwalk + extract-dtb and dtc.
binwalk -e <firmware.bin> extract-dtb.py <extracted firmware dir><uncompressed kernel blob> dtc -I dtb -O dts -o out.dts <extracted dtb that looks right>