On Thu, Jan 08, 2015 at 12:25:18PM +0800, Vince Hsu wrote: > > On 01/07/2015 10:48 PM, Thierry Reding wrote: > >* PGP Signed by an unknown key > > > >On Wed, Jan 07, 2015 at 10:28:29PM +0800, Vince Hsu wrote: > >>On 04:08:52PM Jan 07, Peter De Schrijver wrote: > >>>On Wed, Jan 07, 2015 at 02:27:10PM +0100, Thierry Reding wrote: > >>> > >>>>>Yeah. I plan to have the information of all the clock client of the > >>>>>partitions and > >>>>>the memory clients be defined statically in c source, e.g. pmc-tegra124.c. > >>>>>All modules can declare which domain they belong to in DT. One domain can > >>>>>be really power gated only when no module is awake. Note the clock clients > >>>>>of > >>>>>one domain might not equal to the clocks of the module. The reset is not > >>>>>either. > >>>>>So I don't get the clock and reset from module. How do you think? > >>>>This whole situation is quite messy. The above sequence basically means > >>>>that drivers can't reset hardware modules because otherwise they might > >>>>race with the power domain code. It also means that we can't powergate > >>>The powerdomain framework won't call any powergating method as long as a > >>>module in the domain is still active. So as long as drivers don't try to > >>>reset the hw without having done a pm_runtime_get(), we shouldn't have such > >>>a race? > >>Agree. And as long as the driver has the correct reset procedure, that should > >>be fine to occur between power ungating and gating sequences. > >> > >>>>modules on demand because they might be in the same power domain as one > >>>>other module that's still busy. > >>>> > >>>The powerdomain framework keeps track of which modules are active (by hooking > >>>into runtime pm) and won't try to shutdown a domain unless all modules are > >>>inactive. > >>Yeah. By the way, that means we should start supporting runtime pm for all > >>the modules to use generic power domain. > >Indeed, that'll be a prerequisite before we can merge power domain > >support. I do have a couple of local patches that add very rudimentary > >runtime PM for various drivers. For starters we could probably just do > >the > > > > pm_runtime_enable(...); > > pm_runtime_get_sync(...) > > > >in the ->probe() and > > > > pm_runtime_put_sync(...); > > pm_runtime_disable(...); > > > >in the ->remove() callbacks for those drivers. That's by no means > >optimal but should get us pretty close to what we do now and still > >support the generic power domains. > Cool. Could you send me the patches? Here are two examples: https://github.com/thierryreding/linux/commit/36b5c34f68edb8135b9afb3e62c7ce9a527d6793 https://github.com/thierryreding/linux/commit/6a6145d9e0fcbd4f9599552181fc02f4606b6a0e Thierry
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