Re: [PATCH 6/7] clk: scmi: Allocate CLK operations dynamically

From: Stephen Boyd
Date: Thu Feb 22 2024 - 00:44:36 EST


Quoting Cristian Marussi (2024-02-14 10:30:05)
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index 5747b6d651f0..b91a0dbd2fe0 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -158,51 +158,6 @@ static int scmi_clk_atomic_is_enabled(struct clk_hw *hw)
> return !!enabled;
> }
>
> -/*
> - * We can provide enable/disable/is_enabled atomic callbacks only if the
> - * underlying SCMI transport for an SCMI instance is configured to handle
> - * SCMI commands in an atomic manner.
> - *
> - * When no SCMI atomic transport support is available we instead provide only
> - * the prepare/unprepare API, as allowed by the clock framework when atomic
> - * calls are not available.
> - *
> - * Two distinct sets of clk_ops are provided since we could have multiple SCMI
> - * instances with different underlying transport quality, so they cannot be
> - * shared.
> - */
> -static const struct clk_ops scmi_clk_ops = {
> - .recalc_rate = scmi_clk_recalc_rate,
> - .round_rate = scmi_clk_round_rate,
> - .set_rate = scmi_clk_set_rate,
> - .prepare = scmi_clk_enable,
> - .unprepare = scmi_clk_disable,
> - .set_parent = scmi_clk_set_parent,
> - .get_parent = scmi_clk_get_parent,
> - .determine_rate = scmi_clk_determine_rate,
> -};
> -
> -static const struct clk_ops scmi_atomic_clk_ops = {

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?

> - .recalc_rate = scmi_clk_recalc_rate,
> - .round_rate = scmi_clk_round_rate,
> - .set_rate = scmi_clk_set_rate,
> - .enable = scmi_clk_atomic_enable,
> - .disable = scmi_clk_atomic_disable,
> - .is_enabled = scmi_clk_atomic_is_enabled,