[PATCH 1/2] remoteproc: imx_dsp_rproc: Skip RP_MBOX_SUSPEND_SYSTEM when mailbox TX channel is uninitialized

[Bjorn Andersson]

On Tue, Nov 25, 2025 at 02:49:02PM +0200, Iuliana Prodan (OSS) wrote:
> From: Iuliana Prodan <iuliana.prodan at nxp.com>
> 
> Firmwares that do not use mailbox communication
> (e.g., the hello_world sample) leave priv->tx_ch
> as NULL. The current suspend logic unconditionally
> sends RP_MBOX_SUSPEND_SYSTEM, which is invalid without
> an initialized TX channel.
> 
> Detect the no_mailboxes case early and skip sending
> the suspend message. Instead, proceed directly to
> the runtime PM suspend path, which is the correct
> behavior for firmwares that cannot respond to mailbox
> requests.

Please use the allotted 75 characters of width for your commit message.

> 
> Signed-off-by: Iuliana Prodan <iuliana.prodan at nxp.com>
> ---
>  drivers/remoteproc/imx_dsp_rproc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
> index f11662f9a12f..fc0470aa72c1 100644
> --- a/drivers/remoteproc/imx_dsp_rproc.c
> +++ b/drivers/remoteproc/imx_dsp_rproc.c
> @@ -1308,6 +1308,15 @@ static int imx_dsp_suspend(struct device *dev)
>  	if (rproc->state != RPROC_RUNNING)
>  		goto out;
>  
> +	/*
> +	 * No channel available for sending messages;
> +	 * indicates no mailboxes present, so trigger PM runtime suspend
> +	 */
> +	if (!priv->tx_ch) {
> +		dev_err(dev, "No initialized mbox tx channel\n");

Commit message and comment above says this is "normal" behavior,
dev_err() indicates that it's not. Should this be a dev_info()?

That said, it's still a message every time you suspend, so perhaps even
omitting the print (or a dev_dbg()) makes more sense?

Regards,
Bjorn

> +		goto out;
> +	}
> +
>  	reinit_completion(&priv->pm_comp);
>  
>  	/* Tell DSP that suspend is happening */
> -- 
> 2.34.1
>