remoteproc: qcom: q6v5: Make handover IRQ one-shot

The handover interrupt is expected to be consumed once during each prepare
cycle. If the remote processor keeps signalling handover after the first
event, qcom_q6v5 currently logs the duplicate interrupt repeatedly while
leaving the IRQ enabled.

Track the handover IRQ enable state explicitly and route all handover IRQ
enable/disable operations through idempotent helpers. Request the handover
IRQ with IRQF_NO_AUTOEN so it is only enabled through the helper during
prepare. The handover handler disables it after marking handover as issued,
while unprepare disables and synchronizes it before checking whether
handover was issued.

Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260612-rproc-q6v5-handover-irq-one-shot-v1-1-bb688f4446b3@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

2 files changed, 48 insertions, 10 deletions

diff --git a/drivers/remoteproc/qcom_q6v5.c b/drivers/remoteproc/qcom_q6v5.c
index a11d8ace554b..0206a4a19254 100644
--- a/drivers/remoteproc/qcom_q6v5.c
+++ b/drivers/remoteproc/qcom_q6v5.c
@@ -36,6 +36,40 @@ static int q6v5_load_state_toggle(struct qcom_q6v5 *q6v5, bool enable)
 	return ret;
 }
 
+static void q6v5_handover_irq_enable(struct qcom_q6v5 *q6v5)
+{
+	unsigned long flags;
+	bool enable = false;
+
+	spin_lock_irqsave(&q6v5->handover_lock, flags);
+	if (!q6v5->handover_irq_enabled) {
+		q6v5->handover_irq_enabled = true;
+		enable = true;
+	}
+	spin_unlock_irqrestore(&q6v5->handover_lock, flags);
+
+	if (enable)
+		enable_irq(q6v5->handover_irq);
+}
+
+static void q6v5_handover_irq_disable(struct qcom_q6v5 *q6v5, bool sync)
+{
+	unsigned long flags;
+	bool disable = false;
+
+	spin_lock_irqsave(&q6v5->handover_lock, flags);
+	if (q6v5->handover_irq_enabled) {
+		q6v5->handover_irq_enabled = false;
+		disable = true;
+	}
+	spin_unlock_irqrestore(&q6v5->handover_lock, flags);
+
+	if (disable)
+		disable_irq_nosync(q6v5->handover_irq);
+	if (sync)
+		synchronize_irq(q6v5->handover_irq);
+}
+
 /**
  * qcom_q6v5_prepare() - reinitialize the qcom_q6v5 context before start
  * @q6v5:	reference to qcom_q6v5 context to be reinitialized
@@ -64,7 +98,7 @@ int qcom_q6v5_prepare(struct qcom_q6v5 *q6v5)
 	q6v5->running = true;
 	q6v5->handover_issued = false;
 
-	enable_irq(q6v5->handover_irq);
+	q6v5_handover_irq_enable(q6v5);
 
 	return 0;
 }
@@ -78,7 +112,8 @@ EXPORT_SYMBOL_GPL(qcom_q6v5_prepare);
  */
 int qcom_q6v5_unprepare(struct qcom_q6v5 *q6v5)
 {
-	disable_irq(q6v5->handover_irq);
+	q6v5_handover_irq_disable(q6v5, true);
+
 	q6v5_load_state_toggle(q6v5, false);
 
 	/* Disable interconnect vote, in case handover never happened */
@@ -164,18 +199,15 @@ static irqreturn_t q6v5_handover_interrupt(int irq, void *data)
 {
 	struct qcom_q6v5 *q6v5 = data;
 
-	if (q6v5->handover_issued) {
-		dev_err(q6v5->dev, "Handover signaled, but it already happened\n");
-		return IRQ_HANDLED;
-	}
+	q6v5->handover_issued = true;
+
+	q6v5_handover_irq_disable(q6v5, false);
 
 	if (q6v5->handover)
 		q6v5->handover(q6v5);
 
 	icc_set_bw(q6v5->path, 0, 0);
 
-	q6v5->handover_issued = true;
-
 	return IRQ_HANDLED;
 }
 
@@ -257,6 +289,8 @@ int qcom_q6v5_init(struct qcom_q6v5 *q6v5, struct platform_device *pdev,
 	q6v5->crash_reason = crash_reason;
 	q6v5->handover = handover;
 
+	spin_lock_init(&q6v5->handover_lock);
+
 	init_completion(&q6v5->start_done);
 	init_completion(&q6v5->stop_done);
 
@@ -305,13 +339,13 @@ int qcom_q6v5_init(struct qcom_q6v5 *q6v5, struct platform_device *pdev,
 
 	ret = devm_request_threaded_irq(&pdev->dev, q6v5->handover_irq,
 					NULL, q6v5_handover_interrupt,
-					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT |
+					IRQF_NO_AUTOEN,
 					"q6v5 handover", q6v5);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to acquire handover IRQ\n");
 		return ret;
 	}
-	disable_irq(q6v5->handover_irq);
 
 	q6v5->stop_irq = platform_get_irq_byname(pdev, "stop-ack");
 	if (q6v5->stop_irq < 0)
diff --git a/drivers/remoteproc/qcom_q6v5.h b/drivers/remoteproc/qcom_q6v5.h
index 5a859c41896e..8991ff090579 100644
--- a/drivers/remoteproc/qcom_q6v5.h
+++ b/drivers/remoteproc/qcom_q6v5.h
@@ -5,6 +5,7 @@
 
 #include <linux/kernel.h>
 #include <linux/completion.h>
+#include <linux/spinlock.h>
 #include <linux/soc/qcom/qcom_aoss.h>
 
 struct icc_path;
@@ -29,6 +30,9 @@ struct qcom_q6v5 {
 	int handover_irq;
 	int stop_irq;
 
+	/* Protects handover_irq_enabled against stop/handover races. */
+	spinlock_t handover_lock;
+	bool handover_irq_enabled;
 	bool handover_issued;
 
 	struct completion start_done;