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From:   jqlhn <jqlhn@163.com>
To:     jassisinghbrar@gmail.com
Cc:     linux-kernel@vger.kernel.org, jqlhn <jqlhn@163.com>
Subject: [PATCH] drivers:mailbox Using kfifo to store buffered message data
Date:   Sat,  5 Nov 2022 11:36:23 +0800
Message-Id: <20221105033623.259053-1-jqlhn@163.com>
MIME-Version: 1.0
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In current mailbox, a self implemented message array to be used
as message fifo, I am replacing it with kernel kfifo,
in order to make code cleaner.

Signed-off-by: jqlhn <jqlhn@163.com>
---
 drivers/mailbox/mailbox.c          | 33 ++++++++----------------------
 drivers/mailbox/omap-mailbox.c     |  3 +--
 drivers/mailbox/pcc.c              |  3 +--
 include/linux/mailbox_controller.h | 10 ++++-----
 4 files changed, 14 insertions(+), 35 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 4229b9b5da98..d738bb472cd0 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -25,59 +25,43 @@ static DEFINE_MUTEX(con_mutex);
 
 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
 {
-	int idx;
 	unsigned long flags;
 
 	spin_lock_irqsave(&chan->lock, flags);
 
 	/* See if there is any space left */
-	if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
+	if (kfifo_is_full(&chan->msg_fifo)) {
 		spin_unlock_irqrestore(&chan->lock, flags);
 		return -ENOBUFS;
 	}
 
-	idx = chan->msg_free;
-	chan->msg_data[idx] = mssg;
-	chan->msg_count++;
-
-	if (idx == MBOX_TX_QUEUE_LEN - 1)
-		chan->msg_free = 0;
-	else
-		chan->msg_free++;
+	kfifo_put(&chan->msg_fifo, mssg);
 
 	spin_unlock_irqrestore(&chan->lock, flags);
 
-	return idx;
+	return 0;
 }
 
 static void msg_submit(struct mbox_chan *chan)
 {
-	unsigned count, idx;
 	unsigned long flags;
 	void *data;
 	int err = -EBUSY;
 
 	spin_lock_irqsave(&chan->lock, flags);
 
-	if (!chan->msg_count || chan->active_req)
+	if (!kfifo_peek(&chan->msg_fifo, &data) || chan->active_req)
 		goto exit;
 
-	count = chan->msg_count;
-	idx = chan->msg_free;
-	if (idx >= count)
-		idx -= count;
-	else
-		idx += MBOX_TX_QUEUE_LEN - count;
-
-	data = chan->msg_data[idx];
-
 	if (chan->cl->tx_prepare)
 		chan->cl->tx_prepare(chan->cl, data);
 	/* Try to submit a message to the MBOX controller */
 	err = chan->mbox->ops->send_data(chan, data);
 	if (!err) {
 		chan->active_req = data;
-		chan->msg_count--;
+		/* Get msg out of fifo */
+		if (!kfifo_get(&chan->msg_fifo, &data))
+			err = -ENODATA;
 	}
 exit:
 	spin_unlock_irqrestore(&chan->lock, flags);
@@ -379,8 +363,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 	}
 
 	spin_lock_irqsave(&chan->lock, flags);
-	chan->msg_free = 0;
-	chan->msg_count = 0;
+	INIT_KFIFO(chan->msg_fifo);
 	chan->active_req = NULL;
 	chan->cl = cl;
 	init_completion(&chan->tx_complete);
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 098c82d87137..b392f79e77b3 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -443,8 +443,7 @@ struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
 
 	chan = mbox->chan;
 	spin_lock_irqsave(&chan->lock, flags);
-	chan->msg_free = 0;
-	chan->msg_count = 0;
+	INIT_KFIFO(chan->msg_fifo);
 	chan->active_req = NULL;
 	chan->cl = cl;
 	init_completion(&chan->tx_complete);
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 3c2bc0ca454c..2359cba8381e 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -297,8 +297,7 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
 	dev = chan->mbox->dev;
 
 	spin_lock_irqsave(&chan->lock, flags);
-	chan->msg_free = 0;
-	chan->msg_count = 0;
+	INIT_KFIFO(chan->msg_fifo);
 	chan->active_req = NULL;
 	chan->cl = cl;
 	init_completion(&chan->tx_complete);
diff --git a/include/linux/mailbox_controller.h b/include/linux/mailbox_controller.h
index 6fee33cb52f5..b3bec4f33b6d 100644
--- a/include/linux/mailbox_controller.h
+++ b/include/linux/mailbox_controller.h
@@ -8,6 +8,7 @@
 #include <linux/hrtimer.h>
 #include <linux/device.h>
 #include <linux/completion.h>
+#include <linux/kfifo.h>
 
 struct mbox_chan;
 
@@ -100,7 +101,7 @@ struct mbox_controller {
  * REVISIT: If too many platforms see the "Try increasing MBOX_TX_QUEUE_LEN"
  * print, it needs to be taken from config option or somesuch.
  */
-#define MBOX_TX_QUEUE_LEN	20
+#define MBOX_TX_QUEUE_LEN	32
 
 /**
  * struct mbox_chan - s/w representation of a communication chan
@@ -109,9 +110,7 @@ struct mbox_controller {
  * @cl:			Pointer to the current owner of this channel
  * @tx_complete:	Transmission completion
  * @active_req:		Currently active request hook
- * @msg_count:		No. of mssg currently queued
- * @msg_free:		Index of next available mssg slot
- * @msg_data:		Hook for data packet
+ * @msg_fifo:		Hook for data packet
  * @lock:		Serialise access to the channel
  * @con_priv:		Hook for controller driver to attach private data
  */
@@ -121,8 +120,7 @@ struct mbox_chan {
 	struct mbox_client *cl;
 	struct completion tx_complete;
 	void *active_req;
-	unsigned msg_count, msg_free;
-	void *msg_data[MBOX_TX_QUEUE_LEN];
+	DECLARE_KFIFO(msg_fifo, void*, MBOX_TX_QUEUE_LEN);
 	spinlock_t lock; /* Serialise access to the channel */
 	void *con_priv;
 };
-- 
2.34.1