[PATCH 6.18 309/752] remoteproc: imx_dsp_rproc: Skip RP_MBOX_SUSPEND_SYSTEM when mailbox TX channel is uninitialized

Sasha Levin
2026-02-28T17:52:27Z

From: Iuliana Prodan <iuliana.prodan@nxp.com>

[ Upstream commit d62e0e92e589c53c4320ed5914af5fe103f5ce7e ]

Firmwares that do not use mailbox communication (e.g., the hello_world
sample) leave priv->tx_ch as NULL. The current suspend logic
unconditionally sends RP_MBOX_SUSPEND_SYSTEM, which is invalid without
an initialized TX channel.

Detect the no_mailboxes case early and skip sending the suspend
message. Instead, proceed directly to the runtime PM suspend path,
which is the correct behavior for firmwares that cannot respond to
mailbox requests.

Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Link: https://lore.kernel.org/r/20251204122825.756106-1-iuliana.prodan@oss.nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/remoteproc/imx_dsp_rproc.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
index e61a08df113e4..c0c2bda4964a7 100644
--- a/drivers/remoteproc/imx_dsp_rproc.c
+++ b/drivers/remoteproc/imx_dsp_rproc.c
@@ -1303,6 +1303,15 @@ static int imx_dsp_suspend(struct device *dev)
if (rproc->state != RPROC_RUNNING)
goto out;

+ /*
+ * No channel available for sending messages;
+ * indicates no mailboxes present, so trigger PM runtime suspend
+ */
+ if (!priv->tx_ch) {
+ dev_dbg(dev, "No initialized mbox tx channel, suspend directly.\n");
+ goto out;
+ }
+
reinit_completion(&priv->pm_comp);

/* Tell DSP that suspend is happening */
--
2.51.0