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From:   Markus Schneider-Pargmann <msp@baylibre.com>
To:     Marc Kleine-Budde <mkl@pengutronix.de>,
        Chandrasekar Ramakrishnan <rcsekar@samsung.com>,
        Wolfgang Grandegger <wg@grandegger.com>
Cc:     Vincent MAILHOL <mailhol.vincent@wanadoo.fr>,
        Simon Horman <simon.horman@corigine.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-can@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Julien Panis <jpanis@baylibre.com>,
        Markus Schneider-Pargmann <msp@baylibre.com>
Subject: [PATCH v4 04/12] can: m_can: Add rx coalescing ethtool support
Date:   Wed, 21 Jun 2023 11:23:42 +0200
Message-Id: <20230621092350.3130866-5-msp@baylibre.com>
In-Reply-To: <20230621092350.3130866-1-msp@baylibre.com>
References: <20230621092350.3130866-1-msp@baylibre.com>
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Add the possibility to set coalescing parameters with ethtool.

rx-frames-irq and rx-usecs-irq can only be set and unset together as the
implemented mechanism would not work otherwise. rx-frames-irq can't be
greater than the RX FIFO size.

Also all values can only be changed if the chip is not active.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
---
 drivers/net/can/m_can/m_can.c | 46 +++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 781f287e7ce4..5238a5967971 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1944,8 +1944,54 @@ static const struct net_device_ops m_can_netdev_ops = {
 	.ndo_change_mtu = can_change_mtu,
 };
 
+static int m_can_get_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *ec,
+			      struct kernel_ethtool_coalesce *kec,
+			      struct netlink_ext_ack *ext_ack)
+{
+	struct m_can_classdev *cdev = netdev_priv(dev);
+
+	ec->rx_max_coalesced_frames_irq = cdev->rx_max_coalesced_frames_irq;
+	ec->rx_coalesce_usecs_irq = cdev->rx_coalesce_usecs_irq;
+
+	return 0;
+}
+
+static int m_can_set_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *ec,
+			      struct kernel_ethtool_coalesce *kec,
+			      struct netlink_ext_ack *ext_ack)
+{
+	struct m_can_classdev *cdev = netdev_priv(dev);
+
+	if (cdev->can.state != CAN_STATE_STOPPED) {
+		netdev_err(dev, "Device is in use, please shut it down first\n");
+		return -EBUSY;
+	}
+
+	if (ec->rx_max_coalesced_frames_irq > cdev->mcfg[MRAM_RXF0].num) {
+		netdev_err(dev, "rx-frames-irq %u greater than the RX FIFO %u\n",
+			   ec->rx_max_coalesced_frames_irq,
+			   cdev->mcfg[MRAM_RXF0].num);
+		return -EINVAL;
+	}
+	if (ec->rx_max_coalesced_frames_irq == 0 != ec->rx_coalesce_usecs_irq == 0) {
+		netdev_err(dev, "rx-frames-irq and rx-usecs-irq can only be set together\n");
+		return -EINVAL;
+	}
+
+	cdev->rx_max_coalesced_frames_irq = ec->rx_max_coalesced_frames_irq;
+	cdev->rx_coalesce_usecs_irq = ec->rx_coalesce_usecs_irq;
+
+	return 0;
+}
+
 static const struct ethtool_ops m_can_ethtool_ops = {
+	.supported_coalesce_params = ETHTOOL_COALESCE_RX_USECS_IRQ |
+		ETHTOOL_COALESCE_RX_MAX_FRAMES_IRQ,
 	.get_ts_info = ethtool_op_get_ts_info,
+	.get_coalesce = m_can_get_coalesce,
+	.set_coalesce = m_can_set_coalesce,
 };
 
 static int register_m_can_dev(struct net_device *dev)
-- 
2.40.1