-----Original Message----- From: coreboot-bounces@coreboot.org [mailto:coreboot-bounces@coreboot.org] On Behalf Of Roman Yeryomin Sent: Tuesday, November 04, 2008 10:39 AM To: coreboot@coreboot.org Subject: [coreboot] and/or busybox issue with alix2c3 serial console
I'm experimenting with coreboot (v3) on alix2c3 and still can't get serial console working. :( It stops right after kernel is done booting (I can see coreboot, filo and kernel messages just fine). I use openWRT but tried also another busybox based distribution (imedialinux) -- same problem. With original tinybios no problem. At the same time I tried voyage linux (without busybox) with corebooted alix and it has no such problem. It's obvious that this problem cannot be identified as 100% busybox's (why then it works on tinybios?). While digging coreboot sources I've noticed that uart initialization is done twice for this board -- once in /southbridge/amd/cs5536/cs5536.c (based on dts config) and second time in /mainboard/pcengines/alix2c3/stage1.c. I tried playing with these (and /southbridge/amd/cs5536/stage1.c), disabling one code or another, but no luck. Tried to set MOD bits:
msr.lo = (1 << 4) | (1 << 5) | (1 << 6); msr.hi = 0; wrmsr(MDD_UART1_MOD, msr);Also no luck. Not enabling upper banks, however, makes uart appear in kernel as regular 16550A (and not as NS16550):
/* Bit 1 = DEVEN (device enable) * Bit 4 = EN_BANKS (allow access to the upper banks) */ //msr.lo = (1 << 4) | (1 << 1); msr.lo = 1 << 1; msr.hi = 0;So... where should I go now? I'm really stuck. Begging for help...
We've seen this before on s2892, SimNOW, and other platforms. Has anyone ever nailed this down? I would say that it's definitely not busybox's problem since you don't get any kernel output at all. I didn't know where to look either.
Thanks, Myles