remoteproc: imx_dsp_rproc: Skip RP_MBOX_SUSPEND_SYSTEM when mailbox TX channel is...

[ 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>

diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
index 5a9a8fa031f6d7a4bbbae53aefe50fc9100babe4..9e4f50e0e822ddfbb2778a1dea48fda21f79f222 100644 (file)
--- a/drivers/remoteproc/imx_dsp_rproc.c
+++ b/drivers/remoteproc/imx_dsp_rproc.c
@@ -1260,6 +1260,15 @@ 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 */