linux-kernel - [PATCH v2 04/11] can: m_can: Count TXE FIFO getidx in the driver

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Message-Id: <20221206115728.1056014-5-msp@baylibre.com>
Date:   Tue,  6 Dec 2022 12:57:21 +0100
From:   Markus Schneider-Pargmann <msp@...libre.com>
To:     Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        Wolfgang Grandegger <wg@...ndegger.com>
Cc:     linux-can@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Markus Schneider-Pargmann <msp@...libre.com>
Subject: [PATCH v2 04/11] can: m_can: Count TXE FIFO getidx in the driver

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>
---
 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 45c718413abf..a133f15fb90a 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1020,15 +1020,13 @@ 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) {
@@ -1042,6 +1040,7 @@ 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);
-- 
2.38.1