Re: [PATCH v5 2/3] remoteproc: imx_rproc: skip clock enable when M-core is managed by the SCU

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Hi Hiago,

On Tue, Jun 17, 2025 at 04:34:49PM -0300, Hiago De Franco wrote:
> From: Hiago De Franco <hiago.franco@toradex.com>
> 
> For the i.MX8X and i.MX8 family SoCs, when the M-core is powered up
> by the bootloader, M-core and Linux are in same SCFW (System Controller
> Firmware) partition, so linux has permission to control M-core.

Ok

> 
> But when M-core is started, the SCFW will automatically enable the clock

I find the "But when M-core is started" part confusing.  Started by who?  And
are you making a distinction between "powered up" and "started"?  It is not
possible for someone that doesn't have HW documentation to understand what is
going on. 

> and configure the rate, and any users that want to enable the clock will
> get error 'LOCKED' from SCFW. So current imx_rproc.c probe function
> fails because clk_prepare_enable also fails. With that, the M-core power
> domain is powered off when it is still running, causing a SCU (System
> Controller Unit) fault reset, and the system restarts.
> 
> To address the issue, ignore handling the clk for i.MX8X and i.MX8 M-core,
> because SCFW will automatically enable and configure the clock.
> 
> Suggested-by: Peng Fan <peng.fan@nxp.com>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
> ---
> v4 -> v5:
>  - Unchanged.
> v3 -> v4:
>  - Unchanged.
> v2 -> v3:
>  - Unchanged.
> v1 -> v2:
>  - Commit description updated, as suggested. Fixed Peng Fan email.
> ---
>  drivers/remoteproc/imx_rproc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 74299af1d7f1..627e57a88db2 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -1029,8 +1029,8 @@ static int imx_rproc_clk_enable(struct imx_rproc *priv)
>  	struct device *dev = priv->dev;
>  	int ret;
>  
> -	/* Remote core is not under control of Linux */
> -	if (dcfg->method == IMX_RPROC_NONE)
> +	/* Remote core is not under control of Linux or it is managed by SCU API */
> +	if (dcfg->method == IMX_RPROC_NONE || dcfg->method == IMX_RPROC_SCU_API)
>  		return 0;
>  
>  	priv->clk = devm_clk_get(dev, NULL);
> -- 
> 2.39.5
>