Messages in this thread | | | From | Jeremy Kerr <> | Subject | Re: Locking in the clk API | Date | Tue, 11 Jan 2011 12:11:29 +0800 |
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Hi Paul,
> This looks like a complete disaster, and is also completely inconsistent > with how the API is being used by the vast majority of users today.
I've been basing this on the mxc clock code, which acquires a mutex for all clk_enable()s. This may not be representative of the majority of clock usage.
From a quick search there are a few other cases of non-atomic clock usage:
tcc: clk_enable() acquires a global clocks_mutex tegra: has a clk_enable_cansleep() davinci: clk_set_parent() aquires a global clocks_mutex
Excluding the davinci code (we won't worry about set_parent for now...), if we can port mxc and tcc to a sleepable clk_enable, perhaps we could just go with purely atomic operations.
We'd still need some method of using sleeping clocks though. How about making clk_enable() BUG if the clock is not atomic, and add clk_enable_cansleep() for the cases where clk->ops.enable may sleep.
Do we need something similar for other parts of the API? (clk_set_rate?)
Cheers,
Jeremy
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