[RFC PATCH] can: flexcan: add ethtool support to get rx/tx ring parameters

[Dario Binacchi <dario.binacchi@amarulasolutions.com>]

Adds ethtool support to get the number of message buffers configured for
reception/transmission, which may also depends on runtime configurations
such as the 'rx-rtr' flag state.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

 drivers/net/can/flexcan/flexcan-ethtool.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/net/can/flexcan/flexcan-ethtool.c b/drivers/net/can/flexcan/flexcan-ethtool.c
index 5bb45653e1ac..d119bca584f6 100644
--- a/drivers/net/can/flexcan/flexcan-ethtool.c
+++ b/drivers/net/can/flexcan/flexcan-ethtool.c
@@ -80,7 +80,24 @@ static int flexcan_set_priv_flags(struct net_device *ndev, u32 priv_flags)
 	return 0;
 }
 
+static void flexcan_get_ringparam(struct net_device *ndev,
+				  struct ethtool_ringparam *ring)
+{
+	struct flexcan_priv *priv = netdev_priv(ndev);
+
+	ring->rx_max_pending = priv->mb_count;
+	ring->tx_max_pending = priv->mb_count;
+
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX)
+		ring->rx_pending = __sw_hweight64(priv->rx_mask);
+	else
+		ring->rx_pending = 6;
+
+	ring->tx_pending = __sw_hweight64(priv->tx_mask);
+}
+
 static const struct ethtool_ops flexcan_ethtool_ops = {
+	.get_ringparam = flexcan_get_ringparam,
 	.get_sset_count = flexcan_get_sset_count,
 	.get_strings = flexcan_get_strings,
 	.get_priv_flags = flexcan_get_priv_flags,
-- 
2.32.0