Tushar, On Thu, Jun 5, 2014 at 9:38 PM, Tushar Behera <trblinux@xxxxxxxxx> wrote: > On 06/06/2014 06:38 AM, Doug Anderson wrote: >> Hi, >> >> When I try to boot linuxnext on my exynos5420-peach-pit chromebook I >> have problems bringing up extra CPUs: >> >> 1. They don't come up >> > > [ ... ] > >> [ 1.125030] CPU1: failed to boot: -38 >> [ 2.130043] CPU2: failed to boot: -38 >> [ 3.135059] CPU3: failed to boot: -38 >> > > With following config modifications over exynos_defconfig, I can see 4 > big cores coming up. > > CONFIG_MCPM=y > CONFIG_EXYNOS5420_MCPM=y Thanks! OK, that certainly changes the behavior for me! ...but it doesn't work. I also got a response from some folks that I pinged off-list. Apparently our U-Boot doesn't set things up like the upstream kernel expects (ugh!), so to get things booting you need the magic commands in U-Boot: mw.l 02073028 0 # Clear EXYNOS_START_FLAG mw.l 10d25000 3 # Enable CCI from U-Boot Once you do that then all 8 CPUs can come up! Can someone at Samsung come up with a reasonable solution about how we should solve this in a way that everyone can be happy with? I haven't really been involved with MCPM stuff, so I'm not sure why what landed upstream is different than what we have in our kernel. I guess worst case we can require that anyone running an upstream kernel simply needs a "fixed" U-Boot, but that's always a bit of a hassle. We might have to go there eventually anyway given that our L2 cache timings in U-Boot are wrong (again!) and it's unlikely that upstream will take some weird hack in the kernel to fix them... -Doug P.S. We also really need to do something about the configs. There are no exynos configs upstream that have any useful set of options (that I know of). ...and useful options don't seem to get selected automatically... -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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