[PATCH v3 2/4] hwspinlock: qcom: implement bust operation

[Chris Lew]

From: Richard Maina <quic_rmaina@xxxxxxxxxxx>

Implement a new operation qcom_hwspinlock_bust() which can be invoked
to bust any locks that are in use when a remoteproc is stopped or
crashed.

Signed-off-by: Richard Maina <quic_rmaina@xxxxxxxxxxx>
Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx>
Signed-off-by: Chris Lew <quic_clew@xxxxxxxxxxx>
---
 drivers/hwspinlock/qcom_hwspinlock.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/hwspinlock/qcom_hwspinlock.c b/drivers/hwspinlock/qcom_hwspinlock.c
index 814dfe8697bf..0390979fd765 100644
--- a/drivers/hwspinlock/qcom_hwspinlock.c
+++ b/drivers/hwspinlock/qcom_hwspinlock.c
@@ -64,9 +64,34 @@ static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
 		pr_err("%s: failed to unlock spinlock\n", __func__);
 }
 
+static int qcom_hwspinlock_bust(struct hwspinlock *lock, unsigned int id)
+{
+	struct regmap_field *field = lock->priv;
+	u32 owner;
+	int ret;
+
+	ret = regmap_field_read(field, &owner);
+	if (ret) {
+		dev_err(lock->bank->dev, "unable to query spinlock owner\n");
+		return ret;
+	}
+
+	if (owner != id)
+		return 0;
+
+	ret = regmap_field_write(field, 0);
+	if (ret) {
+		dev_err(lock->bank->dev, "failed to bust spinlock\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static const struct hwspinlock_ops qcom_hwspinlock_ops = {
 	.trylock	= qcom_hwspinlock_trylock,
 	.unlock		= qcom_hwspinlock_unlock,
+	.bust		= qcom_hwspinlock_bust,
 };
 
 static const struct regmap_config sfpb_mutex_config = {

-- 
2.25.1