can: m_can: Add rx coalescing ethtool support

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.

Polling is excluded from irq coalescing support.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/all/20240207093220.2681425-7-msp@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 9b3e8e09f3aa2c0da303cc2573517e0bb80763c9..6dad1f569f820338220d9166498f824d9cf55d74 100644 (file)
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1977,7 +1977,57 @@ 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 const struct ethtool_ops m_can_ethtool_ops_polling = {
        .get_ts_info = ethtool_op_get_ts_info,
 };
 
@@ -1985,7 +2035,10 @@ static int register_m_can_dev(struct net_device *dev)
 {
        dev->flags |= IFF_ECHO; /* we support local echo */
        dev->netdev_ops = &m_can_netdev_ops;
-       dev->ethtool_ops = &m_can_ethtool_ops;
+       if (dev->irq)
+               dev->ethtool_ops = &m_can_ethtool_ops;
+       else
+               dev->ethtool_ops = &m_can_ethtool_ops_polling;
 
        return register_candev(dev);
 }