Hi Maxime, > Am 22.04.2020 um 08:58 schrieb Maxime Ripard <maxime@xxxxxxxxxx>: > > On Tue, Apr 21, 2020 at 07:29:32PM +0200, H. Nikolaus Schaller wrote: >> >>> Am 21.04.2020 um 16:15 schrieb Tony Lindgren <tony@xxxxxxxxxxx>: >>> >>> * Maxime Ripard <maxime@xxxxxxxxxx> [200421 11:22]: >>>> On Tue, Apr 21, 2020 at 11:57:33AM +0200, Philipp Rossak wrote: >>>>> I had a look on genpd and I'm not really sure if that fits. >>>>> >>>>> It is basically some bit that verify that the clocks should be enabled or >>>>> disabled. >>>> >>>> No, it can do much more than that. It's a framework to control the SoCs power >>>> domains, so clocks might be a part of it, but most of the time it's going to be >>>> about powering up a particular device. >>> >>> Note that on omaps there are actually SoC module specific registers. >> >> Ah, I see. This is of course a difference that the TI glue logic has >> its own registers in the same address range as the sgx and this can't >> be easily handled by a common sgx driver. >> >> This indeed seems to be unique with omap. >> >>> And there can be multiple devices within a single target module on >>> omaps. So the extra dts node and device is justified there. >>> >>> For other SoCs, the SGX clocks are probably best handled directly >>> in pvr-drv.c PM runtime functions unless a custom hardware wrapper >>> with SoC specific registers exists. >> >> That is why we need to evaluate what the better strategy is. >> >> So we have >> a) omap which has a custom wrapper around the sgx >> b) others without, i.e. an empty (or pass-through) wrapper >> >> Which one do we make the "standard" and which one the "exception"? >> What are good reasons for either one? >> >> >> I am currently in strong favour of a) being standard because it >> makes the pvr-drv.c simpler and really generic (independent of >> wrapping into any SoC). >> >> This will likely avoid problems if we find more SoC with yet another >> scheme how the SGX clocks are wrapped. >> >> It also allows to handle different number of clocks (A31 seems to >> need 4, Samsung, A83 and JZ4780 one) without changing the sgx bindings >> or making big lists of conditionals. This variance would be handled >> outside the sgx core bindings and driver. > > I disagree. Every other GPU binding and driver is handling that just fine, and > the SGX is not special in any case here. Can you please better explain this? With example or a description or a proposal? I simply do not have your experience with "every other GPU" as you have. And I admit that I can't read from your statement what we should do to bring this topic forward. So please make a proposal how it should be in your view. BR and thanks, Nikolaus
