netdev - [PATCH net-next 32/39] can: m_can: Count TXE FIFO getidx in the driver

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Date:   Mon, 12 Dec 2022 12:30:38 +0100
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de,
        Markus Schneider-Pargmann <msp@...libre.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 32/39] can: m_can: Count TXE FIFO getidx in the driver

From: Markus Schneider-Pargmann <msp@...libre.com>

The getindex simply increases by one for every iteration. There is no
need to get the current getidx every time from a register. Instead we
can just count and wrap if necessary.

Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
Link: https://lore.kernel.org/all/20221206115728.1056014-5-msp@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/m_can/m_can.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 045679af76a0..83d3a7f191bf 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1030,15 +1030,13 @@ static int m_can_echo_tx_event(struct net_device *dev)
 
 	/* Get Tx Event fifo element count */
 	txe_count = FIELD_GET(TXEFS_EFFL_MASK, m_can_txefs);
+	fgi = FIELD_GET(TXEFS_EFGI_MASK, m_can_txefs);
 
 	/* Get and process all sent elements */
 	for (i = 0; i < txe_count; i++) {
 		u32 txe, timestamp = 0;
 		int err;
 
-		/* retrieve get index */
-		fgi = FIELD_GET(TXEFS_EFGI_MASK, m_can_read(cdev, M_CAN_TXEFS));
-
 		/* get message marker, timestamp */
 		err = m_can_txe_fifo_read(cdev, fgi, 4, &txe);
 		if (err) {
@@ -1052,6 +1050,7 @@ static int m_can_echo_tx_event(struct net_device *dev)
 		/* ack txe element */
 		m_can_write(cdev, M_CAN_TXEFA, FIELD_PREP(TXEFA_EFAI_MASK,
 							  fgi));
+		fgi = (++fgi >= cdev->mcfg[MRAM_TXE].num ? 0 : fgi);
 
 		/* update stats */
 		m_can_tx_update_stats(cdev, msg_mark, timestamp);
-- 
2.35.1