[PATCH v2 1/2] can: c_can: add ethtool support

[PATCH v2 1/2] can: c_can: add ethtool support

[Dario Binacchi]

With commit 132f2d45fb23 ("can: c_can: add support to 64 message objects")
the number of message objects used for reception / transmission depends
on FIFO size.
The ethtools API support allows you to retrieve this info. Driver info
has been added too.

Signed-off-by: Dario Binacchi <dariobin@libero.it>

---

Changes in v2:
- Use get_ringparam instead of get_channels

 drivers/net/can/c_can/Makefile                |  3 ++
 drivers/net/can/c_can/c_can.h                 |  2 +
 drivers/net/can/c_can/c_can_ethtool.c         | 44 +++++++++++++++++++
 .../net/can/c_can/{c_can.c => c_can_main.c}   |  1 +
 4 files changed, 50 insertions(+)
 create mode 100644 drivers/net/can/c_can/c_can_ethtool.c
 rename drivers/net/can/c_can/{c_can.c => c_can_main.c} (99%)

diff --git a/drivers/net/can/c_can/Makefile b/drivers/net/can/c_can/Makefile
index e6a94c948531..ac2bca39d6ff 100644
--- a/drivers/net/can/c_can/Makefile
+++ b/drivers/net/can/c_can/Makefile
@@ -4,5 +4,8 @@
 #
 
 obj-$(CONFIG_CAN_C_CAN) += c_can.o
+
+c_can-objs := c_can_main.o c_can_ethtool.o
+
 obj-$(CONFIG_CAN_C_CAN_PLATFORM) += c_can_platform.o
 obj-$(CONFIG_CAN_C_CAN_PCI) += c_can_pci.o
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 06045f610f0e..f9001072514a 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -219,4 +219,6 @@ int c_can_power_up(struct net_device *dev);
 int c_can_power_down(struct net_device *dev);
 #endif
 
+void c_can_set_ethtool_ops(struct net_device *dev);
+
 #endif /* C_CAN_H */
diff --git a/drivers/net/can/c_can/c_can_ethtool.c b/drivers/net/can/c_can/c_can_ethtool.c
new file mode 100644
index 000000000000..1a61bf2fb9ef
--- /dev/null
+++ b/drivers/net/can/c_can/c_can_ethtool.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021, Dario Binacchi <dariobin@libero.it>
+ */
+
+#include <linux/ethtool.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/netdevice.h>
+#include <linux/can/dev.h>
+
+#include "c_can.h"
+
+static void c_can_get_drvinfo(struct net_device *netdev,
+			      struct ethtool_drvinfo *info)
+{
+	struct c_can_priv *priv = netdev_priv(netdev);
+	struct platform_device	*pdev = to_platform_device(priv->device);
+
+	strscpy(info->driver, "c_can", sizeof(info->driver));
+	strscpy(info->version, "1.0", sizeof(info->version));
+	strscpy(info->bus_info, pdev->name, sizeof(info->bus_info));
+}
+
+static void c_can_get_ringparam(struct net_device *netdev,
+				struct ethtool_ringparam *ring)
+{
+	struct c_can_priv *priv = netdev_priv(netdev);
+
+	ring->rx_max_pending = priv->msg_obj_num;
+	ring->tx_max_pending = priv->msg_obj_num;
+	ring->rx_pending = priv->msg_obj_rx_num;
+	ring->tx_pending = priv->msg_obj_tx_num;
+}
+
+static const struct ethtool_ops c_can_ethtool_ops = {
+	.get_drvinfo = c_can_get_drvinfo,
+	.get_ringparam = c_can_get_ringparam,
+};
+
+void c_can_set_ethtool_ops(struct net_device *netdev)
+{
+	netdev->ethtool_ops = &c_can_ethtool_ops;
+}
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can_main.c
similarity index 99%
rename from drivers/net/can/c_can/c_can.c
rename to drivers/net/can/c_can/c_can_main.c
index 313793f6922d..1903b87d5384 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can_main.c
@@ -1335,6 +1335,7 @@ int register_c_can_dev(struct net_device *dev)
 
 	dev->flags |= IFF_ECHO;	/* we support local echo */
 	dev->netdev_ops = &c_can_netdev_ops;
+	c_can_set_ethtool_ops(dev);
 
 	err = register_candev(dev);
 	if (!err)
-- 
2.17.1

Re: [PATCH v2 1/2] can: c_can: add ethtool support

[Andrew Lunn]

On Thu, May 13, 2021 at 09:36:37PM +0200, Dario Binacchi wrote:
> With commit 132f2d45fb23 ("can: c_can: add support to 64 message objects")
> the number of message objects used for reception / transmission depends
> on FIFO size.
> The ethtools API support allows you to retrieve this info. Driver info
> has been added too.

Hi Dario

Nice to see the API being re-used for something other than Ethernet.

> +static void c_can_get_drvinfo(struct net_device *netdev,
> +			      struct ethtool_drvinfo *info)
> +{
> +	struct c_can_priv *priv = netdev_priv(netdev);
> +	struct platform_device	*pdev = to_platform_device(priv->device);
> +
> +	strscpy(info->driver, "c_can", sizeof(info->driver));
> +	strscpy(info->version, "1.0", sizeof(info->version));

version is pretty meaningless. This driver could be backported into
some enterprise kernel with a huge number of patches. Or more likely,
some in car infotainment kernel with a lot of vendor patches. Lots of
things around the driver change, but it still tells you version
1.0. So we don't recommend filling this in. The ethtool core will then
fill the version what kernel the driver is actually being used in:

https://elixir.bootlin.com/linux/latest/source/net/ethtool/ioctl.c#L706

	Andrew