linux-kernel - [PATCH v2 07/11] can: m_can: Batch acknowledge rx fifo

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20221206115728.1056014-8-msp@baylibre.com>
Date:   Tue,  6 Dec 2022 12:57:24 +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 07/11] can: m_can: Batch acknowledge rx fifo

Instead of acknowledging every item of the fifo, only acknowledge the
last item read. This behavior is documented in the datasheet. The new
getindex will be the acknowledged item + 1.

Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
---
 drivers/net/can/m_can/m_can.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 5572a6b3b94c..56f07f2023dd 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -529,9 +529,6 @@ static int m_can_read_fifo(struct net_device *dev, u32 fgi)
 	}
 	stats->rx_packets++;
 
-	/* acknowledge rx fifo 0 */
-	m_can_write(cdev, M_CAN_RXF0A, fgi);
-
 	timestamp = FIELD_GET(RX_BUF_RXTS_MASK, fifo_header.dlc) << 16;
 
 	m_can_receive_skb(cdev, skb, timestamp);
@@ -552,8 +549,9 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
 	u32 rxfs;
 	u32 rx_count;
 	u32 fgi;
+	int ack_fgi = -1;
 	int i;
-	int err;
+	int err = 0;
 
 	rxfs = m_can_read(cdev, M_CAN_RXF0S);
 	if (!(rxfs & RXFS_FFL_MASK)) {
@@ -567,13 +565,20 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
 	for (i = 0; i < rx_count && quota > 0; ++i) {
 		err = m_can_read_fifo(dev, fgi);
 		if (err)
-			return err;
+			break;
 
 		quota--;
 		pkts++;
+		ack_fgi = fgi;
 		fgi = (++fgi >= cdev->mcfg[MRAM_RXF0].num ? 0 : fgi);
 	}
 
+	if (ack_fgi != -1)
+		m_can_write(cdev, M_CAN_RXF0A, ack_fgi);
+
+	if (err)
+		return err;
+
 	return pkts;
 }
 
-- 
2.38.1