remoteproc: k3-m4: Ping the mbox while acquiring the channel

The TI K3 M4 remoteproc driver acquires the mailbox channel in probe but
sends a message through the acquired channel later in .attach()/.start()
callbacks.

Put both the things together in the form of 'k3_m4_rproc_request_mbox()'
function and invoke that in the probe routine. This is done to align the
rproc_request_mbox() implementation with R5 and DSP drivers which can be
factored out at a later stage.

Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
Tested-by: Judith Mendez <jm@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20250513054510.3439842-22-b-padhi@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: 3V3RYONE

drivers/remoteproc/ti_k3_m4_remoteproc.c

@@ -21,11 +21,24 @@
 #include "ti_sci_proc.h"
 #include "ti_k3_common.h"
 
-static int k3_m4_rproc_ping_mbox(struct k3_rproc *kproc)
+static int k3_m4_rproc_request_mbox(struct rproc *rproc)
 {
+	struct k3_rproc *kproc = rproc->priv;
+	struct mbox_client *client = &kproc->client;
 	struct device *dev = kproc->dev;
 	int ret;
 
+	client->dev = dev;
+	client->tx_done = NULL;
+	client->rx_callback = k3_rproc_mbox_callback;
+	client->tx_block = false;
+	client->knows_txdone = false;
+
+	kproc->mbox = mbox_request_channel(client, 0);
+	if (IS_ERR(kproc->mbox))
+		return dev_err_probe(dev, PTR_ERR(kproc->mbox),
+				     "mbox_request_channel failed\n");
+
 	/*
 	 * Ping the remote processor, this is only for sanity-sake for now;
 	 * there is no functional effect whatsoever.
@@ -36,6 +49,7 @@ static int k3_m4_rproc_ping_mbox(struct k3_rproc *kproc)
 	ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_ECHO_REQUEST);
 	if (ret < 0) {
 		dev_err(dev, "mbox_send_message failed: %d\n", ret);
+		mbox_free_channel(kproc->mbox);
 		return ret;
 	}
 
@@ -347,15 +361,8 @@ static void k3_m4_release_tsp(void *data)
 static int k3_m4_rproc_start(struct rproc *rproc)
 {
 	struct k3_rproc *kproc = rproc->priv;
-	int ret;
-
-	ret = k3_m4_rproc_ping_mbox(kproc);
-	if (ret)
-		return ret;
-
-	ret = k3_rproc_release(kproc);
 
-	return ret;
+	return k3_rproc_release(kproc);
 }
 
 /*
@@ -380,13 +387,6 @@ static int k3_m4_rproc_stop(struct rproc *rproc)
  */
 static int k3_m4_rproc_attach(struct rproc *rproc)
 {
-	struct k3_rproc *kproc = rproc->priv;
-	int ret;
-
-	ret = k3_m4_rproc_ping_mbox(kproc);
-	if (ret)
-		return ret;
-
 	return 0;
 }
 
@@ -493,15 +493,9 @@ static int k3_m4_rproc_probe(struct platform_device *pdev)
 		dev_info(dev, "configured M4F for remoteproc mode\n");
 	}
 
-	kproc->client.dev = dev;
-	kproc->client.tx_done = NULL;
-	kproc->client.rx_callback = k3_rproc_mbox_callback;
-	kproc->client.tx_block = false;
-	kproc->client.knows_txdone = false;
-	kproc->mbox = mbox_request_channel(&kproc->client, 0);
-	if (IS_ERR(kproc->mbox))
-		return dev_err_probe(dev, PTR_ERR(kproc->mbox),
-				     "mbox_request_channel failed\n");
+	ret = k3_m4_rproc_request_mbox(rproc);
+	if (ret)
+		return ret;
 
 	ret = devm_rproc_add(dev, rproc);
 	if (ret)