Re: [PATCH v4 3/3] remoteproc: imx_rproc: detect and attach to pre-booted remote cores

[Hiago De Franco <hiagofranco@gmail.com>]

On Wed, Jun 04, 2025 at 03:19:52AM +0000, Peng Fan wrote:
> > Subject: [PATCH v4 3/3] remoteproc: imx_rproc: detect and attach to
> > pre-booted remote cores
> > 
> > From: Hiago De Franco <hiago.franco@toradex.com>
> > 
> > When the remote core is started before Linux boots (e.g., by the
> > bootloader), the driver currently is not able to attach because it only
> > checks for cores running in different partitions. If the core was kicked
> > by the bootloader, it is in the same partition as Linux and it is already
> > up and running.
> > 
> > This adds power mode verification through dev_pm_genpd_is_on(),
> > enabling the driver to detect when the remote core is already running
> > and properly attach to it if all the power domain devices are on.
> > 
> > To accomplish this, we need to avoid passing any attach_data or flags
> > to dev_pm_domain_attach_list(), letting the platform device become a
> > consumer of the power domain provider. With that the current power
> > state of the genpds will not change, allowing the detection of the
> > remote core power state.
> > 
> > We enable and sync the device runtime PM during probe to make sure
> > the power domains are correctly managed when the core is controlled
> > by the kernel.
> > 
> > Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
> > Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
> > ---
> > v4: Changed to use the new dev_pm_genpd_is_on() function instead,
> > as suggested by Ulf. This will now get the power status of the two
> > remote cores power domains to decided if imx_rpoc needs to attach or
> > not. In order to do that, pm_runtime_enable() and
> > pm_runtime_get_sync() were introduced and pd_data was removed.
> > v3: Unchanged.
> > v2: Dropped unecessary include. Removed the imx_rproc_is_on
> > function, as suggested.
> > v1:
> > ---
> >  drivers/remoteproc/imx_rproc.c | 29 ++++++++++++++++++++++++-----
> >  1 file changed, 24 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/remoteproc/imx_rproc.c
> > b/drivers/remoteproc/imx_rproc.c index
> > 627e57a88db2..6f9680142704 100644
> > --- a/drivers/remoteproc/imx_rproc.c
> > +++ b/drivers/remoteproc/imx_rproc.c
> > @@ -18,6 +18,7 @@
> >  #include <linux/of_reserved_mem.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_domain.h>
> > +#include <linux/pm_runtime.h>
> >  #include <linux/reboot.h>
> >  #include <linux/regmap.h>
> >  #include <linux/remoteproc.h>
> > @@ -890,10 +891,8 @@ static int imx_rproc_partition_notify(struct
> > notifier_block *nb,  static int imx_rproc_attach_pd(struct imx_rproc
> > *priv)  {
> >  	struct device *dev = priv->dev;
> > -	int ret;
> > -	struct dev_pm_domain_attach_data pd_data = {
> > -		.pd_flags = PD_FLAG_DEV_LINK_ON,
> > -	};
> > +	int ret, i;
> > +	bool detached = true;
> > 
> >  	/*
> >  	 * If there is only one power-domain entry, the platform driver
> > framework @@ -902,7 +901,22 @@ static int
> > imx_rproc_attach_pd(struct imx_rproc *priv)
> >  	if (dev->pm_domain)
> >  		return 0;
> > 
> > -	ret = dev_pm_domain_attach_list(dev, &pd_data, &priv-
> > >pd_list);
> > +	ret = dev_pm_domain_attach_list(dev, NULL, &priv->pd_list);
> > +	/*
> > +	 * If all the power domain devices are already turned on, the
> > remote
> > +	 * core is already up when the kernel booted (e.g. kicked by
> > the
> > +	 * bootloader). In this case attach to it.
> > +	 */
> > +	for (i = 0; i < ret; i++) {
> > +		if (!dev_pm_genpd_is_on(priv->pd_list->pd_devs[i])) {
> > +			detached = false;
> > +			break;
> > +		}
> > +	}
> > +
> > +	if (detached)
> > +		priv->rproc->state = RPROC_DETACHED;
> > +
> >  	return ret < 0 ? ret : 0;
> >  }
> > 
> > @@ -1146,6 +1160,11 @@ static int imx_rproc_probe(struct
> > platform_device *pdev)
> >  		}
> >  	}
> > 
> > +	if (dcfg->method == IMX_RPROC_SCU_API) {
> > +		pm_runtime_enable(dev);
> > +		pm_runtime_get_sync(dev);
> 
> Need put and disable in imx_rproc_remove.
> 
> BTW: Has this patchset tested with M4 in a separate partition,
> saying M4 image packed in flash.bin?

Sorry for the delay.

I tested it now and there must be something missing on my U-Boot:

Disable imx8x-cm4 rsrc 278 not owned
Disable imx8x-cm4 rsrc 297 not owned

It removes my nodes from the DT before starting the kernel, so I cannot
attach. Do you know what should I do in this case?

But apart from that, at least the imx-rproc does not crash or anything.

> 
> Regards,
> Peng
> > +	}
> > +
> >  	ret = rproc_add(rproc);
> >  	if (ret) {
> >  		dev_err(dev, "rproc_add failed\n");
> > --
> > 2.39.5
> > 
> 

Best Regards,
Hiago.