linux-kernel - Re: [PATCH v2 2/3] clk: ingenic: Mark critical clocks in Ingenic SoCs

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Date:   Wed, 18 May 2022 13:57:52 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Aidan MacDonald <aidanmacdonald.0x0@...il.com>,
        mturquette@...libre.com, tsbogend@...ha.franken.de
Cc:     paulburton@...nel.org, paul@...pouillou.net,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org
Subject: Re: [PATCH v2 2/3] clk: ingenic: Mark critical clocks in Ingenic SoCs

Quoting Aidan MacDonald (2022-04-28 09:44:53)
> Consider CPU, L2 cache, and memory clocks as critical to prevent
> them -- and the parent clocks -- from being automatically gated,
> since nothing calls clk_get() on these clocks.
> 
> Gating the CPU clock hangs the processor, and gating memory makes
> external DRAM inaccessible. Normal kernel code can't hope to deal
> with either situation so those clocks have to be critical.
> 
> The L2 cache is required only if caches are running, and could be
> gated if the kernel takes care to flush and disable caches before
> gating the clock. There's no mechanism to do this, and probably no
> reason to do it, so it's simpler to mark the L2 cache as critical.
> 
> Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@...il.com>
> Reviewed-by: Paul Cercueil <paul@...pouillou.net>
> ---

Applied to clk-next