[PATCH 4/6] misc: sbrmi: Clear sbrmi status register bit SwAlertSts

[Akshay Gupta <akshay.gupta@amd.com>]

- SBRMI register status b1' SwAlertSts sets in below conditions
  - Completion of Mailbox command
  - syncflood event
If the bit is set for syncfllod event, it may be interpretted as
mailbox command compleition. This patch clears the bit before
start of mailbox protocol.

Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
---
 drivers/misc/amd-sb/sbrmi-core.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/misc/amd-sb/sbrmi-core.c b/drivers/misc/amd-sb/sbrmi-core.c
index b2437a4044ac..e528b7314447 100644
--- a/drivers/misc/amd-sb/sbrmi-core.c
+++ b/drivers/misc/amd-sb/sbrmi-core.c
@@ -42,6 +42,22 @@ enum sbrmi_reg {
 	SBRMI_SW_INTERRUPT,
 };
 
+static int sbrmi_clear_status_alert(struct sbrmi_data *data)
+{
+	int sw_status, ret;
+
+	ret = regmap_read(data->regmap, SBRMI_STATUS,
+			  &sw_status);
+	if (ret < 0)
+		return ret;
+
+	if (!(sw_status & SW_ALERT_MASK))
+		return 0;
+
+	return regmap_write(data->regmap, SBRMI_STATUS,
+			    SW_ALERT_MASK);
+}
+
 int rmi_mailbox_xfer(struct sbrmi_data *data,
 		     struct sbrmi_mailbox_msg *msg)
 {
@@ -52,6 +68,10 @@ int rmi_mailbox_xfer(struct sbrmi_data *data,
 
 	mutex_lock(&data->lock);
 
+	ret = sbrmi_clear_status_alert(data);
+	if (ret < 0)
+		goto exit_unlock;
+
 	/* Indicate firmware a command is to be serviced */
 	ret = regmap_write(data->regmap, SBRMI_INBNDMSG7, START_CMD);
 	if (ret < 0)
-- 
2.25.1