Hello Kevin, On Thu, Oct 23, 2014 at 9:26 PM, Kevin Hilman <khilman@xxxxxxxxxx> wrote: > Abhilash Kesavan <a.kesavan@xxxxxxxxxxx> writes: > >> The change was based on my reading of the platsmp file of the >> Odroid-xu3 3.10 kernel and issues experienced previously. From what I >> understand, the platsmp code in 3.10 kernel is trying to reset the A7s >> and my change just bypasses the check (no magic here ). The change was >> only suggested as a workaround to get 8 cores up using MCPM and not an >> actual fix. I had explained this in my mail to Kevin. So, if this >> were to be mainlined we would probably need to use something like >> exynos_core_restart in mcpm along with the workaround. But, this is >> all guesswork on my part and someone with knowledge of the 3.10 >> kernel/bootloader needs to comment. > > Unfortunately, the harkernel tree git repo doesn't help understand where > the change came from because an entire v3.10.y based Samsung BSP is > checked into the tree on top of a v3.8.y kernel in a single commit !!! > > Abhilash, in the absence of the original author, could write up a patch > with your change? > > Or, if you can help me with a detailed changelog, I can work on the patch. > I don't have any exynos docs, so it would be good to have a description > of what reading/writing to that register are actually doing. I could post a patch with an explanation of how I think the workaround works, but there are a few issues: - I am not completely confident that this is the best/right change. - We are adding code to the exynos mcpm back-end to work-around a bootloader setting for Odroid-xu3. We would have to make it specific to odroid somehow as we do not require it for 5420/5800 chromebooks. - This might solve the 8 core boot-up issue but other scenarios might still fail like the one Joonyoung has already reported. > > Also, can you explain what you meant by using exynos_core_restart? I > don't see that function in mainline. It is present in linux-next and kgene's for-next branch as part of this commit "ARM: EXYNOS: SWRESET is needed to boot secondary CPU on exynos3250". Regards, Abhilash -- 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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