> Subject: Re: [PATCH v4 3/3] remoteproc: imx_rproc: detect and attach
> to pre-booted remote cores
>
> 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.fra...@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.hans...@linaro.org>
> > > Signed-off-by: Hiago De Franco <hiago.fra...@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?
In separate partition case, UBoot will check the permission
by checking the rsrc-id, saying power domain id.
You may need to remove the power-domains property
from M4 node.
Regards,
Peng
>
> 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.
