linux-kernel - Re: [PATCH v3] remoteproc: xlnx: allow single core use in split mode

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Message-ID: <aFlzzSvUsstEQsKP@p14s>
Date: Mon, 23 Jun 2025 09:33:33 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Tanmay Shah <tanmay.shah@....com>
Cc: andersson@...nel.org, linux-remoteproc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] remoteproc: xlnx: allow single core use in split mode

On Wed, Jun 18, 2025 at 11:19:33AM -0700, Tanmay Shah wrote:
> When operating in split mode, it is a valid usecase to have
> only one core enabled in the cluster. Remove exact core count
> expecatation from the driver.
> 
> Signed-off-by: Tanmay Shah <tanmay.shah@....com>
> ---
> 
> Changes in v3:
>   - Fix commit message
>   - Add details about split mode configuration in comment
> 
> Change in v2:
>   - limit core_count to max 2
> 
>  drivers/remoteproc/xlnx_r5_remoteproc.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)

Merged.

Thanks,
Mathieu

> 
> diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c b/drivers/remoteproc/xlnx_r5_remoteproc.c
> index 1af89782e116..5aa3fd1b0530 100644
> --- a/drivers/remoteproc/xlnx_r5_remoteproc.c
> +++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
> @@ -1329,19 +1329,23 @@ static int zynqmp_r5_cluster_init(struct zynqmp_r5_cluster *cluster)
>  
>  	/*
>  	 * Number of cores is decided by number of child nodes of
> -	 * r5f subsystem node in dts. If Split mode is used in dts
> -	 * 2 child nodes are expected.
> +	 * r5f subsystem node in dts.
> +	 * In split mode maximum two child nodes are expected.
> +	 * However, only single core can be enabled too.
> +	 * Driver can handle following configuration in split mode:
> +	 * 1) core0 enabled, core1 disabled
> +	 * 2) core0 disabled, core1 enabled
> +	 * 3) core0 and core1 both are enabled.
> +	 * For now, no more than two cores are expected per cluster
> +	 * in split mode.
>  	 * In lockstep mode if two child nodes are available,
>  	 * only use first child node and consider it as core0
>  	 * and ignore core1 dt node.
>  	 */
>  	core_count = of_get_available_child_count(dev_node);
> -	if (core_count == 0) {
> +	if (core_count == 0 || core_count > 2) {
>  		dev_err(dev, "Invalid number of r5 cores %d", core_count);
>  		return -EINVAL;
> -	} else if (cluster_mode == SPLIT_MODE && core_count != 2) {
> -		dev_err(dev, "Invalid number of r5 cores for split mode\n");
> -		return -EINVAL;
>  	} else if (cluster_mode == LOCKSTEP_MODE && core_count == 2) {
>  		dev_warn(dev, "Only r5 core0 will be used\n");
>  		core_count = 1;
> 
> base-commit: d293da1e4dbebb40560e4c6a417b29ce3393659a
> -- 
> 2.34.1
>