ref: b4c916efce5e1476d9ac7079ca8ffec54fdcbce2
dir: /sys/src/9/mt7688/words/
9 Front kernel for the MediaTek MT7688 currently tested on; Onion Omega 2 Hi-Link HKL7688A FPU Emulation; The MIPS24KEc core used in the MT7688 does not have a FPU. Because of the way Mips does branch delay slots, tos.h needs to include a scratch space for fpimips.c /* scratch space for kernel use (e.g., mips fp delay-slot execution) */ ulong kscr[4]; /* top of stack is here */ Since lots of things use tos.h, the enitre spim environment needs to be nuked and reinstalled to keep things consistent. Build Environment; Because libc for spim ends up using a combination of portable code, and mips and spim machine specific code, I have seen some issues where things being built in the wrong order causes failure in the kernel. For best results; cd /sys/src objtype=spim mk nuke mk libs mk install Drivers; The first UART, often documented as "UART Lite" or "UARTL", is set up, but no others. The MT7688 has 1 Ethernet device wired directly into a 7 port switch, usually on port 5. Port 0 is typically used as the WAN port on routers, and ports 1-4 are the LAN ports. Right now, the Ethernet driver, ether7688.c, just sets up the switch to run ports 1-5 as a simple unmanaged switch to allow outside connections. This has been tested on the HKL7688A, but not on the Onion Omega 2 with the Ethernet expansion. WiFi, SPI, I²C, GPIO, USB, MMC, and a dedicated switch driver are works in progress. u-boot; The kernel currently assumes that it will be loaded at 0x80020000 and that plan9.ini will be loaded at 0x80010000 (CONFADDR) nvram; In order to connect to your auth and fileserver, copy a nvram with the credentials you want into a file, and add the location of that file (ex. /usr/ glenda/nvram) to the bootdir section of the kernel configuration file (mt7688). In plan9.ini, specify to use the nvram in the /boot directory in the kernel; nvram=/boot/nvram nvroff=0 nvrlen=512 Erratum 48; There is a known issue with the 24K series cores, where data is lost if 3 cache writes are done in a row. The mips linker in some legacy Plan 9 distributions has a change in vl/noop.c where it can be set to insert a no-op between stores to avoid this issue.