Re: [PATCH V4 2/2] clk: scmi: support state_ctrl_forbidden

Sudeep Holla
2024-02-22T09:42:03Z

On Sun, Jan 21, 2024 at 07:09:01PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> Some clocks may exported to linux, while those clocks are not allowed
> to configure by Linux. For example:
>
> SYS_CLK1-----
> \
> --MUX--->MMC1_CLK
> /
> SYS_CLK2-----
>
> MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
> then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
> So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
> the clock of MMC1, adding scmi_no_state_ctrl_clk_ops to use software
> enable counter, while not calling scmi api.
>
> Co-developed-by: Cristian Marussi <cristian.marussi@arm.com>
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>
> V4:
> Add scmi_no_state_ctrl_clk_ops per Cristian
> Add Cristian's tag
>
> V3:
> Add check in atomic enable
>
> V2:
> New. Take Cristian's suggestion
>
> drivers/clk/clk-scmi.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index 8cbe24789c24..5747b6d651f0 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -194,6 +194,15 @@ static const struct clk_ops scmi_atomic_clk_ops = {
> .determine_rate = scmi_clk_determine_rate,
> };
>
> +static const struct clk_ops scmi_no_state_ctrl_clk_ops = {
> + .recalc_rate = scmi_clk_recalc_rate,
> + .round_rate = scmi_clk_round_rate,
> + .set_rate = scmi_clk_set_rate,
> + .set_parent = scmi_clk_set_parent,
> + .get_parent = scmi_clk_get_parent,
> + .determine_rate = scmi_clk_determine_rate,
> +};
> +
> static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
> const struct clk_ops *scmi_ops)
> {
> @@ -290,8 +299,10 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
> * specify (or support) an enable_latency associated with a
> * clock, we default to use atomic operations mode.
> */
> - if (is_atomic &&
> - sclk->info->enable_latency <= atomic_threshold)
> + if (sclk->info->state_ctrl_forbidden)
> + scmi_ops = &scmi_no_state_ctrl_clk_ops;

With this, even if is_atomic and latency matches, we won't allow
atomic operations ? One reason why it gets tricky and as Cristian
mentioned elsewhere we need dynamic assignment of these ops IMO.
Let me know if I am getting things wrong here ?

--
Regards,
Sudeep