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Wysocki" , Peng Fan Subject: Re: [PATCH v7 3/3] remoteproc: imx_rproc: detect and attach to pre-booted remote cores Message-ID: References: <20250716132552.bra37ucw4fcjwril@hiagonb> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250716132552.bra37ucw4fcjwril@hiagonb> On Wed, Jul 16, 2025 at 10:25:52AM -0300, Hiago De Franco wrote: > Hi Mathieu, Ulf, > > On Tue, Jul 15, 2025 at 09:32:44AM -0600, Mathieu Poirier wrote: > > On Sun, Jun 29, 2025 at 02:25:12PM -0300, Hiago De Franco wrote: > > > From: Hiago De Franco > > > > > > 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 > > > Reviewed-by: Ulf Hansson > > > Reviewed-by: Peng Fan > > > Signed-off-by: Hiago De Franco > > > --- > > > 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 > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -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. > > As Ulf pointed out, the 'return' a few lines below will return the > negative value to the caller of 'imx_rproc_attach_pd', which ultimately > will fail 'imx_rproc_detect_mode' and fail the probe of imx_rproc. > > Please notice that even tough 'dev_pm_domain_attach_list' fails, the > rproc->state will still be set as RPROC_DETACHED because we are starting > 'detached' as true, but I am not seeing this as an issue because as > mentioned above the probe will fail anyway. Please let me know if you > see this as an issue. Two things to consider here: (1) It is only a matter of time before someone with a cleaver coccinelle script sends me a patch that adds the missing error check. (2) I think that @rproc->state being changed on error conditions is a bug waiting to happen. This kind of implicit error handling is difficult to maintain and even more difficult for people to make enhancements to the driver. Adding a simple error check will make sure neither of the above will happen. It is a simple change and we are at rc6 - this work can still go in the merge window. > > > > > Thanks, > > Mathieu > > > > > + > > > + 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 > > > > > On Tue, Jul 15, 2025 at 06:03:44PM +0200, Ulf Hansson wrote: > > On Tue, 15 Jul 2025 at 17:32, Mathieu Poirier > > wrote: > > > > > > On Sun, Jun 29, 2025 at 02:25:12PM -0300, Hiago De Franco wrote: > > > > From: Hiago De Franco > > > > > > > > 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 > > > > Reviewed-by: Ulf Hansson > > > > Reviewed-by: Peng Fan > > > > Signed-off-by: Hiago De Franco > > > > --- > > > > 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 > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > #include > > > > @@ -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 > > > > > > Best Regards, > > Hiago.