Messages in this thread | | | Date | Thu, 29 Feb 2024 10:09:10 +0000 | From | Cristian Marussi <> | Subject | Re: [PATCH 6/7] clk: scmi: Allocate CLK operations dynamically |
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On Wed, Feb 28, 2024 at 06:20:34PM -0800, Stephen Boyd wrote: > Quoting Cristian Marussi (2024-02-22 00:28:41) > > On Wed, Feb 21, 2024 at 09:44:14PM -0800, Stephen Boyd wrote: > > > > > > It's not great to move these function pointer structs out of RO memory > > > to RW. I'm also not convinced that it's any better to construct them at > > > runtime. Isn't there a constant set of possible clk configurations? Or > > > why can't we simply add some failures to the clk_ops functions instead? > > > > Well, the real clock devices managed by the SCMI server can be a of > > SCMI is a server!? :) >
..well the platform fw act as a server in the client-server SCMI model...so...I know these days it's cooler to be "serverless" but..hey... ..at least is not a BO2k server :P
> > varying nature and so the minimum set of possible clk configurations > > to cover will amount to all the possible combinations of supported ops > > regarding the specific clock properties (i.e. .set_parent / .set_rate / > > .enable / .get/set_duty_cycle / atomic_capability ... for now)...we > > simply cannot know in advance what the backend SCMI server is handling. > > > > These seemed to me too much in number (and growing) to be pre-allocated > > in all possible combinations. (and mostly wasted since you dont really > > probably use all combinations all the time) > > > > Moreover, SCMI latest spec now exposes some clock properties (or not) to > > be able avoid even sending an actual SCMI message that we know will be > > denied all the time; one option is that we return an error,, as you said, > > but what is the point (I thought) to provide at all a clk-callback that > > we know upfront will fail to be executed every time ? (and some consumer > > drivers have been reported by partners not to be happy with these errors) > > > > What I think could be optimized here instead, and I will try in the next > > respin, it is that now I am allocating one set of custom ops for each clock > > at the end, even if exactly the same ops are provided since the clock > > capabilities are the same; I could instead allocate dynamically and fill only > > one single set of ops for each distinct set of combinations, so as to avoid > > useless duplication and use only the miminum strict amount of RW memory > > needed. > > > > Yes please don't allocate a clk_op per clk. And, please add these > answers to the commit text so that we know why it's not possible to know > all combinations or fail clk_ops calls.
Sure I posted this series a couple of days ago about this rework:
https://lore.kernel.org/linux-arm-kernel/20240227194812.1209532-1-cristian.marussi@arm.com/
with a bit of context in the cover-letter and in the commit...but I can add more commenting of course if needed.
Thanks for the review, Cristian
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