[PATCH v3 3/3] remoteproc: imx_rproc: add power mode check for remote core attachment

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

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 the SCU interface, enabling
the driver to detect when the remote core is already running and
properly attach to it.

Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
Suggested-by: Peng Fan <peng.fan@nxp.com>
---
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 | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 627e57a88db2..9b6e9e41b7fc 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -949,6 +949,19 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
 			if (of_property_read_u32(dev->of_node, "fsl,entry-address", &priv->entry))
 				return -EINVAL;
 
+			/*
+			 * If remote core is already running (e.g. kicked by
+			 * the bootloader), attach to it.
+			 */
+			ret = imx_sc_pm_get_resource_power_mode(priv->ipc_handle,
+								priv->rsrc_id);
+			if (ret < 0)
+				dev_err(dev, "failed to get power resource %d mode, ret %d\n",
+					priv->rsrc_id, ret);
+
+			if (ret == IMX_SC_PM_PW_MODE_ON)
+				priv->rproc->state = RPROC_DETACHED;
+
 			return imx_rproc_attach_pd(priv);
 		}
 
-- 
2.39.5