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

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Message-Id: <20250602131906.25751-4-hiagofranco@gmail.com>
Date: Mon,  2 Jun 2025 10:19:05 -0300
From: Hiago De Franco <hiagofranco@...il.com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	linux-pm@...r.kernel.org,
	linux-remoteproc@...r.kernel.org
Cc: 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>
Subject: [PATCH v4 3/3] remoteproc: imx_rproc: detect and attach to pre-booted remote cores

From: Hiago De Franco <hiago.franco@...adex.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@...aro.org>
Signed-off-by: Hiago De Franco <hiago.franco@...adex.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: https://lore.kernel.org/lkml/20250505154849.64889-4-hiagofranco@gmail.com/
---
 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);
+	}
+
 	ret = rproc_add(rproc);
 	if (ret) {
 		dev_err(dev, "rproc_add failed\n");
-- 
2.39.5