On 10 June 2014 04:08, Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote: > On Mon, Jun 09, 2014 at 06:03:31PM +0100, Doug Anderson wrote: > > [...] > >> Cold boot and resume from suspend are detected via various special >> flags in various special locations. Resume from suspend looks at >> INFORM1 (0x10048004) for flags. This register is 0 during a cold boot >> and has special values set by the kernel at resume time. >> >> It also looks as if some code looks at 0x10040900 (PMU_SPARE0) to help >> tell initial cold boot and secondary CPU bringup. > > Ok, thanks a lot. It looks like firmware paths should be ready to > detect cold vs warm boot, and hopefully do not rely on a specific > MPIDR to come up first out of power states. > >> > I am asking to check if on this platform CPUidle (where the notion of >> > primary CPU disappears) has a chance to run properly. >> >> I believe it should be possible, but we don't have CPUidle implemented >> in our current system. Abhilash may be able to comment more. > Cpuidle is implemented for exynos5420, and is tested on chromebook. > I am interested in more insights, that's very helpful thanks. > >> > Probably CPUidle won't attain idle states where IRAM content is lost, but I >> > am still worried about the primary vs secondaries firmware boot behaviour. >> >> I don't think iRAM can be turned off for CPUidle. Yes thats true. > > It might be added a system state but I doubt that too and if you are > relying on registers for jump addresses that's not even a problem in > the first place. > >> > What happens on reboot from suspend to RAM (or to put it differently, >> > what does secure firmware do on reboot from suspend to RAM - in >> > particular how is the "jump" address to bootloader/kernel set ?) >> >> Should be described above now. > > Thank you very much. > > Lorenzo > > -- > 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 -- with warm regards, Chander Kashyap -- 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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