On Wednesday 21 May 2014 11:02:29 Daniel Lezcano wrote: > On 05/21/2014 10:10 AM, Arnd Bergmann wrote: > > On Wednesday 21 May 2014 09:15:34 Daniel Lezcano wrote: > >> On 05/15/2014 10:40 PM, Kukjin Kim wrote: > >> > >> [ ... ] > >> > >>>>>> Exynos cpuidle is not a device on the SoC, so I don't think there is > >>>>>> any > >>>>>> way to represent it in DT. The only thing I could see this is matching > >>>>>> root node with a central SoC driver that instantiates specific > >>>>>> subdevices, such as cpufreq and cpuidle, but I don't see any available > >>>>>> infrastructure for this. > >>>>> > >>>>> There is a RFC for defining generic idle states [1]. > >>>>> > >>>>> The idea behind using the platform driver framework is to unify the code > >>>>> across the different drivers and separate the PM / cpuidle code. > >>>>> > >>>>> By this way, we can move the different drivers to drivers/cpuidle and > >>>>> store them in a single place. That make easier the tracking, the review > >>>>> and the maintenance. > > > > Yes, that would be great. I only looked briefly at the series now, doesn't > > that require the use of psci? > > No, because PSCI is for some specific platform (eg. calxeda), all the > other drivers are legacy and manually handling the PM via some low level > callbacks. This is why all drivers were implemented all over the place > making so difficult to maintain them. Little by little, we split the PM > callbacks from the idle algorithm so reducing the platform dependency > with the generic code. > > The PSCI implements such PM callbacks in the firmware directly and are > accessed through an API. PSCI is, let's say some kindof nextgen cpuidle. > It is similar than mwait on Intel. But if a new platform does not have > such firmware, then the cpuidle driver will have the legacy format. Ok, thanks for the exlanation. Arnd -- 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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