[can-next-rfc 04/12] can: mcp251xfd: ethtool: add support

[Marc Kleine-Budde <mkl@pengutronix.de>]

This patch adds basic ethtool support (to query the current and
maximum ring parameters) to the driver.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/spi/mcp251xfd/Makefile        |  1 +
 .../net/can/spi/mcp251xfd/mcp251xfd-core.c    |  2 ++
 .../net/can/spi/mcp251xfd/mcp251xfd-ethtool.c | 35 +++++++++++++++++++
 .../net/can/spi/mcp251xfd/mcp251xfd-ring.c    |  4 +++
 drivers/net/can/spi/mcp251xfd/mcp251xfd.h     |  2 ++
 5 files changed, 44 insertions(+)
 create mode 100644 drivers/net/can/spi/mcp251xfd/mcp251xfd-ethtool.c

diff --git a/drivers/net/can/spi/mcp251xfd/Makefile b/drivers/net/can/spi/mcp251xfd/Makefile
index 10c4f886d1f7..94d7de954294 100644
--- a/drivers/net/can/spi/mcp251xfd/Makefile
+++ b/drivers/net/can/spi/mcp251xfd/Makefile
@@ -6,6 +6,7 @@ mcp251xfd-objs :=
 mcp251xfd-objs += mcp251xfd-chip-fifo.o
 mcp251xfd-objs += mcp251xfd-core.o
 mcp251xfd-objs += mcp251xfd-crc16.o
+mcp251xfd-objs += mcp251xfd-ethtool.o
 mcp251xfd-objs += mcp251xfd-ram.o
 mcp251xfd-objs += mcp251xfd-regmap.o
 mcp251xfd-objs += mcp251xfd-ring.o
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 3da17cadbd63..ebb4dc999bac 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -1871,6 +1871,8 @@ static int mcp251xfd_register(struct mcp251xfd_priv *priv)
 	if (err)
 		goto out_chip_sleep;
 
+	mcp251xfd_ethtool_init(priv);
+
 	err = register_candev(ndev);
 	if (err)
 		goto out_chip_sleep;
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ethtool.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ethtool.c
new file mode 100644
index 000000000000..4131185eaf5a
--- /dev/null
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ethtool.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// mcp251xfd - Microchip MCP251xFD Family CAN controller driver
+//
+// Copyright (c) 2021, 2022 Pengutronix,
+//               Marc Kleine-Budde <kernel@pengutronix.de>
+//
+
+#include <linux/ethtool.h>
+
+#include "mcp251xfd.h"
+
+static void
+mcp251xfd_ring_get_ringparam(struct net_device *ndev,
+			     struct ethtool_ringparam *ring,
+			     struct kernel_ethtool_ringparam *kernel_ring,
+			     struct netlink_ext_ack *extack)
+{
+	const struct mcp251xfd_priv *priv = netdev_priv(ndev);
+
+	ring->rx_max_pending = MCP251XFD_RX_OBJ_NUM_MAX;
+	ring->tx_max_pending = MCP251XFD_TX_OBJ_NUM_MAX;
+
+	ring->rx_pending = priv->rx_obj_num;
+	ring->tx_pending = priv->tx->obj_num;
+}
+
+static const struct ethtool_ops mcp251xfd_ethtool_ops = {
+	.get_ringparam = mcp251xfd_ring_get_ringparam,
+};
+
+void mcp251xfd_ethtool_init(struct mcp251xfd_priv *priv)
+{
+	priv->ndev->ethtool_ops = &mcp251xfd_ethtool_ops;
+}
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
index b1c4d9b19347..e540c97b4160 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
@@ -304,6 +304,8 @@ int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
 		rx_obj_size = sizeof(struct mcp251xfd_hw_rx_obj_can);
 	}
 
+	priv->rx_obj_num = 0;
+
 	tx_ring = priv->tx;
 	tx_ring->obj_num = tx_obj_num;
 	tx_ring->obj_size = tx_obj_size;
@@ -320,6 +322,8 @@ int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
 		rx_obj_num = min(1 << (fls(rx_obj_num) - 1),
 				 MCP251XFD_RX_OBJ_NUM_MAX);
 
+		priv->rx_obj_num += rx_obj_num;
+
 		rx_ring = kzalloc(sizeof(*rx_ring) + rx_obj_size * rx_obj_num,
 				  GFP_KERNEL);
 		if (!rx_ring) {
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
index 87cc13d455c1..5c7a672464b1 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -610,6 +610,7 @@ struct mcp251xfd_priv {
 	struct mcp251xfd_tx_ring tx[MCP251XFD_FIFO_TX_NUM];
 
 	u8 rx_ring_num;
+	u8 rx_obj_num;
 
 	struct mcp251xfd_ecc ecc;
 	struct mcp251xfd_regs_status regs_status;
@@ -891,6 +892,7 @@ int mcp251xfd_chip_fifo_init(const struct mcp251xfd_priv *priv);
 u16 mcp251xfd_crc16_compute2(const void *cmd, size_t cmd_size,
 			     const void *data, size_t data_size);
 u16 mcp251xfd_crc16_compute(const void *data, size_t data_size);
+void mcp251xfd_ethtool_init(struct mcp251xfd_priv *priv);
 int mcp251xfd_regmap_init(struct mcp251xfd_priv *priv);
 int mcp251xfd_ring_init(struct mcp251xfd_priv *priv);
 void mcp251xfd_ring_free(struct mcp251xfd_priv *priv);
-- 
2.35.1