linux-kernel - Re: [PATCH] clk: qcom: rpmh: Set wake/sleep state for BCM clks

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Date:   Wed, 4 May 2022 11:53:54 -0500
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        patches@...ts.linux.dev, Alex Elder <elder@...aro.org>,
        Taniya Das <quic_tdas@...cinc.com>
Subject: Re: [PATCH] clk: qcom: rpmh: Set wake/sleep state for BCM clks

On Tue 12 Apr 14:45 CDT 2022, Stephen Boyd wrote:

> Set the wake and sleep state for BCM clks here, not just the active
> state, as the active only state is dropped when CPUs go to deep idle.
> This ensures the clk is always on when the driver thinks it is on.
> 
> This was found by inspection, and could very well be incorrect if the
> RPMh hardware copies over the active only state to the sleep and wake
> states.
> 

Taking another look at this patch and now it makes perfect sense to me.
Sorry for not grasping the problem earlier.

Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>


Will you take this in fixes, or do you want me to pick it for 5.19?

> Cc: Alex Elder <elder@...aro.org>
> Cc: Taniya Das <quic_tdas@...cinc.com>
> Fixes: 04053f4d23a4 ("clk: qcom: clk-rpmh: Add IPA clock support")
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
>  drivers/clk/qcom/clk-rpmh.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clk-rpmh.c b/drivers/clk/qcom/clk-rpmh.c
> index aed907982344..29da1ffd10cf 100644
> --- a/drivers/clk/qcom/clk-rpmh.c
> +++ b/drivers/clk/qcom/clk-rpmh.c
> @@ -260,6 +260,7 @@ static int clk_rpmh_bcm_send_cmd(struct clk_rpmh *c, bool enable)
>  	struct tcs_cmd cmd = { 0 };
>  	u32 cmd_state;
>  	int ret = 0;
> +	enum rpmh_state state;
>  
>  	mutex_lock(&rpmh_clk_lock);
>  	if (enable) {
> @@ -274,15 +275,19 @@ static int clk_rpmh_bcm_send_cmd(struct clk_rpmh *c, bool enable)
>  		cmd.addr = c->res_addr;
>  		cmd.data = BCM_TCS_CMD(1, enable, 0, cmd_state);
>  
> -		ret = clk_rpmh_send(c, RPMH_ACTIVE_ONLY_STATE, &cmd, enable);
> -		if (ret) {
> -			dev_err(c->dev, "set active state of %s failed: (%d)\n",
> -				c->res_name, ret);
> -		} else {
> -			c->last_sent_aggr_state = cmd_state;
> +		for (state = RPMH_SLEEP_STATE; state <= RPMH_ACTIVE_ONLY_STATE; state++) {
> +			ret = clk_rpmh_send(c, state, &cmd, enable);

Nit. We only need to pass the positive enable on the last iteration here...

Regards,
Bjorn

> +			if (ret) {
> +				dev_err(c->dev, "set %s state of %s failed: (%d)\n",
> +					!state ? "sleep" :
> +					state == RPMH_WAKE_ONLY_STATE	?
> +					"wake" : "active", c->res_name, ret);
> +				goto out;
> +			}
>  		}
> +		c->last_sent_aggr_state = cmd_state;
>  	}
> -
> +out:
>  	mutex_unlock(&rpmh_clk_lock);
>  
>  	return ret;
> 
> base-commit: 3123109284176b1532874591f7c81f3837bbdc17
> -- 
> https://chromeos.dev
>