br2chenxing

A Buildroot external for MStar/SigmaStar (Chenxing) SoCs. It provides the u-boot/kernel defaults for a full Chenxing board build plus a handful of packages:

• libge — userspace library for the MStar/SigmaStar GE 2D engine (/dev/mstar-ge).
• directfb2-ge — DirectFB2 graphics driver that offloads DirectFB blits, fills and lines to the GE via libge (selects libge; needs directfb2).
• snander — SPI-NAND/NOR flasher.
• isptool, mstarbintools — host tools for talking to MStar chips and manipulating their binaries.

Using it

Point Buildroot at this tree with BR2_EXTERNAL (it can be combined with other externals by separating paths with :), then select the packages you want:

make -C /path/to/buildroot BR2_EXTERNAL=/path/to/br2chenxing O=$PWD/output <defconfig>
make -C /path/to/buildroot BR2_EXTERNAL=/path/to/br2chenxing O=$PWD/output menuconfig
make -C /path/to/buildroot BR2_EXTERNAL=/path/to/br2chenxing O=$PWD/output

The kernel/u-boot defaults (repos, ipl SPL name, DTB support, ...) are applied only for a full Chenxing build, i.e. when BR2_CHENXING is selected; enabling a single package (e.g. directfb2-ge) on an unrelated config won't drag them in.

GE-accelerated DirectFB2

Enable BR2_PACKAGE_DIRECTFB2_GE (with BR2_PACKAGE_DIRECTFB2 and its DRM/KMS system). At runtime the GE driver only engages when DirectFB uses PRIME file descriptors, so start apps with --dfb:drmkms-use-prime-fd. libge needs the drm/mstar_ge.h UAPI header, which the Chenxing kernel headers provide.