Abhilash Kesavan <kesavan.abhilash@xxxxxxxxx> writes: > 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. Maybe post as RFC. > - 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. Hmm, if you have an idea how/where to fix it in u-boot, I'd be glad to give that a try. I'm using the hardkernel u-boot repo: https://github.com/hardkernel/u-boot.git, branch odroidxu3-v2012.07, and would be happy to test any fixes there. > - This might solve the 8 core boot-up issue but other scenarios might > still fail like the one Joonyoung has already reported. I replied yesterday to that report, and the one Joonyoung reported exists with or without your proposed fix, so I don't think they're directly related. >> >> 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". OK, I see it now. Kevin -- 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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