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From: Mikko Perttunen <mperttunen@nvidia.com>
To: <robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<jassisinghbrar@gmail.com>, <gregkh@linuxfoundation.org>,
	<thierry.reding@gmail.com>, <jonathanh@nvidia.com>
Cc: <araza@nvidia.com>, <devicetree@vger.kernel.org>,
	<linux-serial@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	"Mikko Perttunen" <mperttunen@nvidia.com>
Subject: [PATCH 3/8] mailbox: Add transmit done by blocking option
Date: Tue, 8 May 2018 14:43:58 +0300	[thread overview]
Message-ID: <20180508114403.14499-4-mperttunen@nvidia.com> (raw)
In-Reply-To: <20180508114403.14499-1-mperttunen@nvidia.com>

Add a new TXDONE option, TXDONE_BY_BLOCK. With this option, the
send_data function of the mailbox driver is expected to block until
the message has been sent. The new option is used with the Tegra
Combined UART driver to minimize unnecessary overhead when transmitting
data.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
 drivers/mailbox/mailbox.c | 30 +++++++++++++++++++++---------
 drivers/mailbox/mailbox.h |  1 +
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 674b35f402f5..5c76b70e673c 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -53,6 +53,8 @@ static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
 	return idx;
 }
 
+static void tx_tick(struct mbox_chan *chan, int r, bool submit_next);
+
 static void msg_submit(struct mbox_chan *chan)
 {
 	unsigned count, idx;
@@ -60,10 +62,13 @@ static void msg_submit(struct mbox_chan *chan)
 	void *data;
 	int err = -EBUSY;
 
+next:
 	spin_lock_irqsave(&chan->lock, flags);
 
-	if (!chan->msg_count || chan->active_req)
-		goto exit;
+	if (!chan->msg_count || chan->active_req) {
+		spin_unlock_irqrestore(&chan->lock, flags);
+		return;
+	}
 
 	count = chan->msg_count;
 	idx = chan->msg_free;
@@ -82,15 +87,21 @@ static void msg_submit(struct mbox_chan *chan)
 		chan->active_req = data;
 		chan->msg_count--;
 	}
-exit:
+
 	spin_unlock_irqrestore(&chan->lock, flags);
 
 	if (!err && (chan->txdone_method & TXDONE_BY_POLL))
 		/* kick start the timer immediately to avoid delays */
 		hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL);
+
+	if (chan->txdone_method & TXDONE_BY_BLOCK) {
+		tx_tick(chan, err, false);
+		if (!err)
+			goto next;
+	}
 }
 
-static void tx_tick(struct mbox_chan *chan, int r)
+static void tx_tick(struct mbox_chan *chan, int r, bool submit_next)
 {
 	unsigned long flags;
 	void *mssg;
@@ -101,7 +112,8 @@ static void tx_tick(struct mbox_chan *chan, int r)
 	spin_unlock_irqrestore(&chan->lock, flags);
 
 	/* Submit next message */
-	msg_submit(chan);
+	if (submit_next)
+		msg_submit(chan);
 
 	if (!mssg)
 		return;
@@ -127,7 +139,7 @@ static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
 		if (chan->active_req && chan->cl) {
 			txdone = chan->mbox->ops->last_tx_done(chan);
 			if (txdone)
-				tx_tick(chan, 0);
+				tx_tick(chan, 0, true);
 			else
 				resched = true;
 		}
@@ -176,7 +188,7 @@ void mbox_chan_txdone(struct mbox_chan *chan, int r)
 		return;
 	}
 
-	tx_tick(chan, r);
+	tx_tick(chan, r, true);
 }
 EXPORT_SYMBOL_GPL(mbox_chan_txdone);
 
@@ -196,7 +208,7 @@ void mbox_client_txdone(struct mbox_chan *chan, int r)
 		return;
 	}
 
-	tx_tick(chan, r);
+	tx_tick(chan, r, true);
 }
 EXPORT_SYMBOL_GPL(mbox_client_txdone);
 
@@ -275,7 +287,7 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 		ret = wait_for_completion_timeout(&chan->tx_complete, wait);
 		if (ret == 0) {
 			t = -ETIME;
-			tx_tick(chan, t);
+			tx_tick(chan, t, true);
 		}
 	}
 
diff --git a/drivers/mailbox/mailbox.h b/drivers/mailbox/mailbox.h
index 456ba68513bb..ec68e2e28cd6 100644
--- a/drivers/mailbox/mailbox.h
+++ b/drivers/mailbox/mailbox.h
@@ -10,5 +10,6 @@
 #define TXDONE_BY_IRQ	BIT(0) /* controller has remote RTR irq */
 #define TXDONE_BY_POLL	BIT(1) /* controller can read status of last TX */
 #define TXDONE_BY_ACK	BIT(2) /* S/W ACK recevied by Client ticks the TX */
+#define TXDONE_BY_BLOCK	BIT(3) /* mailbox driver send_data blocks until done */
 
 #endif /* __MAILBOX_H */
-- 
2.16.1

  parent reply	other threads:[~2018-05-08 11:43 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-08 11:43 [PATCH 0/8] Tegra Combined UART driver Mikko Perttunen
2018-05-08 11:43 ` [PATCH 1/8] dt-bindings: tegra186-hsp: Add shared interrupts Mikko Perttunen
2018-05-22 15:15   ` Jon Hunter
2018-06-19 12:41     ` Mikko Perttunen
2018-05-08 11:43 ` [PATCH 2/8] dt-bindings: serial: Add bindings for nvidia,tegra194-tcu Mikko Perttunen
2018-05-22 15:15   ` Jon Hunter
2018-05-22 20:18     ` Rob Herring
2018-05-22 20:20   ` Rob Herring
2018-05-08 11:43 ` Mikko Perttunen [this message]
2018-05-08 11:43 ` [PATCH 4/8] mailbox: tegra-hsp: Refactor in preparation of mailboxes Mikko Perttunen
2018-05-22 15:36   ` Jon Hunter
2018-06-19 12:52     ` Mikko Perttunen
2018-05-08 11:44 ` [PATCH 5/8] mailbox: tegra-hsp: Add support for shared mailboxes Mikko Perttunen
2018-05-22 16:20   ` Jon Hunter
2018-05-08 11:44 ` [PATCH 6/8] serial: Add Tegra Combined UART driver Mikko Perttunen
2018-05-13 14:16   ` Andy Shevchenko
2018-05-13 18:04     ` Mikko Perttunen
2018-05-13 22:20       ` Andy Shevchenko
2018-05-14  7:36         ` Mikko Perttunen
2018-05-13 15:36   ` Jassi Brar
2018-05-13 18:06     ` Mikko Perttunen
2018-05-08 11:44 ` [PATCH 7/8] arm64: tegra: Add nodes for tcu on Tegra194 Mikko Perttunen
2018-05-22 16:28   ` Jon Hunter
2018-05-08 11:44 ` [PATCH 8/8] arm64: tegra: Mark tcu as primary serial port on Tegra194 P2888 Mikko Perttunen
2018-05-22 16:29   ` Jon Hunter

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