From: Corey Minyard <cminyard@mvista.com>
Date: Wed, 25 Jan 2023 10:34:47 -0600
Subject: [PATCH] ipmi:ssif: Add a timer between request retries
Patch-mainline: v6.3-rc1
Git-commit: 00bb7e763ec9f384cb382455cb6ba5588b5375cf
References: bsc#1206459

The IPMI spec has a time (T6) specified between request retries.  Add
the handling for that.

Reported by: Tony Camuso <tcamuso@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Chester Lin <clin@suse.com>
---
 drivers/char/ipmi/ipmi_ssif.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index c25c4b1a03ae..a5ddebb1edea 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -74,7 +74,8 @@
 /*
  * Timer values
  */
-#define SSIF_MSG_USEC		60000	/* 60ms between message tries. */
+#define SSIF_MSG_USEC		60000	/* 60ms between message tries (T3). */
+#define SSIF_REQ_RETRY_USEC	60000	/* 60ms between send retries (T6). */
 #define SSIF_MSG_PART_USEC	5000	/* 5ms for a message part */
 
 /* How many times to we retry sending/receiving the message. */
@@ -82,7 +83,9 @@
 #define	SSIF_RECV_RETRIES	250
 
 #define SSIF_MSG_MSEC		(SSIF_MSG_USEC / 1000)
+#define SSIF_REQ_RETRY_MSEC	(SSIF_REQ_RETRY_USEC / 1000)
 #define SSIF_MSG_JIFFIES	((SSIF_MSG_USEC * 1000) / TICK_NSEC)
+#define SSIF_REQ_RETRY_JIFFIES	((SSIF_REQ_RETRY_USEC * 1000) / TICK_NSEC)
 #define SSIF_MSG_PART_JIFFIES	((SSIF_MSG_PART_USEC * 1000) / TICK_NSEC)
 
 /*
@@ -229,6 +232,9 @@ struct ssif_info {
 	bool		    got_alert;
 	bool		    waiting_alert;
 
+	/* Used to inform the timeout that it should do a resend. */
+	bool		    do_resend;
+
 	/*
 	 * If set to true, this will request events the next time the
 	 * state machine is idle.
@@ -531,22 +537,28 @@ static void start_get(struct ssif_info *ssif_info)
 		  ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
 }
 
+static void start_resend(struct ssif_info *ssif_info);
+
 static void retry_timeout(struct timer_list *t)
 {
 	struct ssif_info *ssif_info = from_timer(ssif_info, t, retry_timer);
 	unsigned long oflags, *flags;
-	bool waiting;
+	bool waiting, resend;
 
 	if (ssif_info->stopping)
 		return;
 
 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
+	resend = ssif_info->do_resend;
+	ssif_info->do_resend = false;
 	waiting = ssif_info->waiting_alert;
 	ssif_info->waiting_alert = false;
 	ipmi_ssif_unlock_cond(ssif_info, flags);
 
 	if (waiting)
 		start_get(ssif_info);
+	if (resend)
+		start_resend(ssif_info);
 }
 
 static void watch_timeout(struct timer_list *t)
@@ -595,8 +607,6 @@ static void ssif_alert(struct i2c_client *client, enum i2c_alert_protocol type,
 		start_get(ssif_info);
 }
 
-static void start_resend(struct ssif_info *ssif_info);
-
 static void msg_done_handler(struct ssif_info *ssif_info, int result,
 			     unsigned char *data, unsigned int len)
 {
@@ -901,7 +911,13 @@ static void msg_written_handler(struct ssif_info *ssif_info, int result,
 	if (result < 0) {
 		ssif_info->retries_left--;
 		if (ssif_info->retries_left > 0) {
-			start_resend(ssif_info);
+			/*
+			 * Wait the retry timeout time per the spec,
+			 * then redo the send.
+			 */
+			ssif_info->do_resend = true;
+			mod_timer(&ssif_info->retry_timer,
+				  jiffies + SSIF_REQ_RETRY_JIFFIES);
 			return;
 		}
 
@@ -1311,8 +1327,10 @@ static int do_cmd(struct i2c_client *client, int len, unsigned char *msg,
 	ret = i2c_smbus_write_block_data(client, SSIF_IPMI_REQUEST, len, msg);
 	if (ret) {
 		retry_cnt--;
-		if (retry_cnt > 0)
+		if (retry_cnt > 0) {
+			msleep(SSIF_REQ_RETRY_MSEC);
 			goto retry1;
+		}
 		return -ENODEV;
 	}
 
@@ -1453,8 +1471,10 @@ static int start_multipart_test(struct i2c_client *client,
 					 32, msg);
 	if (ret) {
 		retry_cnt--;
-		if (retry_cnt > 0)
+		if (retry_cnt > 0) {
+			msleep(SSIF_REQ_RETRY_MSEC);
 			goto retry_write;
+		}
 		dev_err(&client->dev, "Could not write multi-part start, though the BMC said it could handle it.  Just limit sends to one part.\n");
 		return ret;
 	}
-- 
2.37.3