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Message-ID: <CAPDyKFrWng0CY-ayKoEbnS_yanghSqogxfuizxEVbVogJ4DT=g@mail.gmail.com>
Date: Tue, 15 Jul 2025 18:03:44 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Mathieu Poirier <mathieu.poirier@...aro.org>
Cc: Hiago De Franco <hiagofranco@...il.com>, linux-pm@...r.kernel.org,
linux-remoteproc@...r.kernel.org, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>, Bjorn Andersson <andersson@...nel.org>,
Hiago De Franco <hiago.franco@...adex.com>, imx@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Peng Fan <peng.fan@....nxp.com>, daniel.baluta@....com, iuliana.prodan@....nxp.com,
"Rafael J . Wysocki" <rafael@...nel.org>, Peng Fan <peng.fan@....com>
Subject: Re: [PATCH v7 3/3] remoteproc: imx_rproc: detect and attach to
pre-booted remote cores
On Tue, 15 Jul 2025 at 17:32, Mathieu Poirier
<mathieu.poirier@...aro.org> wrote:
>
> On Sun, Jun 29, 2025 at 02:25:12PM -0300, Hiago De Franco wrote:
> > From: Hiago De Franco <hiago.franco@...adex.com>
> >
> > When the Cortex-M remote core is started and already running before
> > Linux boots (typically by the Cortex-A bootloader using a command like
> > bootaux), the current driver is unable to attach to it. This is because
> > the driver only checks for remote cores running in different SCFW
> > partitions. However in this case, the M-core is in the same partition as
> > Linux and is already powered up and running by the bootloader.
> >
> > This patch adds a check using dev_pm_genpd_is_on() to verify whether the
> > M-core's power domains are already on. If all power domain devices are
> > on, the driver assumes the M-core is running and proceed to attach to
> > it.
> >
> > To accomplish this, we need to avoid passing any attach_data or flags to
> > dev_pm_domain_attach_list(), allowing the platform device become a
> > consumer of the power domain provider without changing its current
> > state.
> >
> > During probe, also enable and sync the device runtime PM to make sure
> > the power domains are correctly managed when the core is controlled by
> > the kernel.
> >
> > Suggested-by: Ulf Hansson <ulf.hansson@...aro.org>
> > Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
> > Reviewed-by: Peng Fan <peng.fan@....com>
> > Signed-off-by: Hiago De Franco <hiago.franco@...adex.com>
> > ---
> > v6 -> v7:
> > - Added Peng reviewed-by.
> > v5 -> v6:
> > - Commit description improved, as suggested. Added Ulf Hansson reviewed
> > by. Comment on imx-rproc.c improved.
> > v4 -> v5:
> > - pm_runtime_get_sync() removed in favor of
> > pm_runtime_resume_and_get(). Now it also checks the return value of
> > this function.
> > - Added pm_runtime_disable() and pm_runtime_put() to imx_rproc_remove()
> > function.
> > v3 -> 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.
> > v2 -> v3:
> > - Unchanged.
> > v1 -> v2:
> > - Dropped unecessary include. Removed the imx_rproc_is_on function, as
> > suggested.
> > ---
> > drivers/remoteproc/imx_rproc.c | 37 +++++++++++++++++++++++++++++-----
> > 1 file changed, 32 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> > index 627e57a88db2..24597b60c5b0 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 powered up and running when the kernel booted (e.g.,
> > + * started by U-Boot's bootaux command). 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;
> > + }
> > + }
>
> I was doing one final review of this work when I noticed the return code for
> dev_pm_domain_attach_list() is never checked for error.
The for loop covers the error condition correctly, I think. It's only
when ret >=1 when the loop should be started - and ret is propagated
to the caller a few lines below.
>
> Thanks,
> Mathieu
>
Kind regards
Uffe
> > +
> > + if (detached)
> > + priv->rproc->state = RPROC_DETACHED;
> > +
> > return ret < 0 ? ret : 0;
> > }
> >
> > @@ -1146,6 +1160,15 @@ static int imx_rproc_probe(struct platform_device *pdev)
> > }
> > }
> >
> > + if (dcfg->method == IMX_RPROC_SCU_API) {
> > + pm_runtime_enable(dev);
> > + ret = pm_runtime_resume_and_get(dev);
> > + if (ret) {
> > + dev_err(dev, "pm_runtime get failed: %d\n", ret);
> > + goto err_put_clk;
> > + }
> > + }
> > +
> > ret = rproc_add(rproc);
> > if (ret) {
> > dev_err(dev, "rproc_add failed\n");
> > @@ -1171,6 +1194,10 @@ static void imx_rproc_remove(struct platform_device *pdev)
> > struct rproc *rproc = platform_get_drvdata(pdev);
> > struct imx_rproc *priv = rproc->priv;
> >
> > + if (priv->dcfg->method == IMX_RPROC_SCU_API) {
> > + pm_runtime_disable(priv->dev);
> > + pm_runtime_put(priv->dev);
> > + }
> > clk_disable_unprepare(priv->clk);
> > rproc_del(rproc);
> > imx_rproc_put_scu(rproc);
> > --
> > 2.39.5
> >
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