linux-kernel - Re: [PATCH v2 3/9] remoteproc: qcom_q6v5_mss: Handle platforms with one power domain

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Message-ID: <Z5dKxZ-fri8RaTPo@linaro.org>
Date: Mon, 27 Jan 2025 09:58:45 +0100
From: Stephan Gerhold <stephan.gerhold@...aro.org>
To: Luca Weiss <luca@...aweiss.eu>
Cc: ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
	Bjorn Andersson <andersson@...nel.org>,
	Mathieu Poirier <mathieu.poirier@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Stephan Gerhold <stephan@...hold.net>,
	Konrad Dybcio <konradybcio@...nel.org>,
	Matti Lehtimäki <matti.lehtimaki@...il.com>,
	linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/9] remoteproc: qcom_q6v5_mss: Handle platforms with
 one power domain

On Sun, Jan 26, 2025 at 09:57:22PM +0100, Luca Weiss wrote:
> For example MSM8974 has mx voltage rail exposed as regulator and only cx
> voltage rail is exposed as power domain. This power domain (cx) is
> attached internally in power domain and cannot be attached in this driver.
> 
> Fixes: 8750cf392394 ("remoteproc: qcom_q6v5_mss: Allow replacing regulators with power domains")
> Co-developed-by: Matti Lehtimäki <matti.lehtimaki@...il.com>
> Signed-off-by: Matti Lehtimäki <matti.lehtimaki@...il.com>
> Signed-off-by: Luca Weiss <luca@...aweiss.eu>
> ---
> Changes in v2:
>   - Move MSM8974 mx-supply from "fallback_proxy_supply" to
>     "proxy_supply" to match updated DT schema
>   - Add fixes tag
> ---
>  drivers/remoteproc/qcom_q6v5_mss.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
> index e78bd986dc3f256effce4470222c0a5faeea86ec..e2523b01febf393abfe50740a68b85a04011293c 100644
> --- a/drivers/remoteproc/qcom_q6v5_mss.c
> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> @@ -1828,6 +1828,13 @@ static int q6v5_pds_attach(struct device *dev, struct device **devs,
>  	if (!pd_names)
>  		return 0;
>  
> +	/* Handle single power domain */
> +	if (dev->pm_domain) {
> +		devs[0] = dev;
> +		pm_runtime_enable(dev);
> +		return 1;
> +	}
> +
>  	while (pd_names[num_pds])
>  		num_pds++;

Hmm, I think you should put the above if condition below this loop and
verify that num_pds == 1. Otherwise this would hide the error condition
if the platform needs multple PDs, but someone only specifies one of
them in the DT. i.e.

	if (num_pds == 1 && dev->pm_domain) {
		// ...
	}

>  
> @@ -1851,8 +1858,15 @@ static int q6v5_pds_attach(struct device *dev, struct device **devs,
>  static void q6v5_pds_detach(struct q6v5 *qproc, struct device **pds,
>  			    size_t pd_count)
>  {
> +	struct device *dev = qproc->dev;
>  	int i;
>  
> +	/* Handle single power domain */
> +	if (dev->pm_domain && pd_count) {

Maybe if (pd_count == 1 && dev->pm_domain) for consistency with the
above then.

> +		pm_runtime_disable(dev);

I'm guessing it does, but just to make sure: Have you verified that the
power domain is indeed voted for off after this call to
pm_runtime_disable()? Start the remoteproc and when it's booted inspect
/sys/kernel/debug/pm_genpd/pm_genpd_summary to see if the PD/remoteproc
dev is suspended.

Thanks,
Stephan