[PATCH v1 22/24] can: kvaser_usb: advertise timestamping capabilities and add ioctl support

[Vincent Mailhol <mailhol.vincent@wanadoo.fr>]

Currently, userland has no method to query which timestamping features
are supported by the kvaser_usb driver (aside maybe of getting RX
messages and obseverse whever or not hardware timestamps stay at
zero).

The canonical way for a network driver to advertise what kind of
timestamping it supports is to implement
ethtool_ops::get_ts_info(). Here, we use the CAN specific
can_ethtool_op_get_ts_info_hwts() function to achieve this.

In addition, the driver currently does not support the hardware
timestamps ioctls. According to [1], SIOCSHWTSTAMP is "must" and
SIOCGHWTSTAMP is "should". This patch fills up that gap by
implementing net_device_ops::ndo_eth_ioctl() using the CAN specific
function can_eth_ioctl_hwts().

[1] kernel doc Timestamping, section 3.1: "Hardware Timestamping
Implementation: Device Drivers"
Link: https://docs.kernel.org/networking/timestamping.html#hardware-timestamping-implementation-device-drivers

CC: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---

Hi Jimmy, as far as I understand, only the hydra has the hardware
timestamping. If not the case, let me know.

This is not tested. If you find any issue or if you want to modify,
feel free to pick up that patch and resend it.
---
 drivers/net/can/usb/kvaser_usb/kvaser_usb.h   |  1 +
 .../net/can/usb/kvaser_usb/kvaser_usb_core.c  | 25 ++++++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb.h b/drivers/net/can/usb/kvaser_usb/kvaser_usb.h
index eefcbe3aadce..841da29cef93 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb.h
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb.h
@@ -39,6 +39,7 @@
 #define KVASER_USB_QUIRK_HAS_SILENT_MODE	BIT(0)
 #define KVASER_USB_QUIRK_HAS_TXRX_ERRORS	BIT(1)
 #define KVASER_USB_QUIRK_IGNORE_CLK_FREQ	BIT(2)
+#define KVASER_USB_QUIRK_HAS_HARDWARE_TIMESTAMP	BIT(3)
 
 /* Device capabilities */
 #define KVASER_USB_CAP_BERR_CAP			0x01
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
index 964c0026383e..36e896dbd94b 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -92,7 +92,7 @@
 #define USB_HYBRID_PRO_CANLIN_PRODUCT_ID	278
 
 static const struct kvaser_usb_driver_info kvaser_usb_driver_info_hydra = {
-	.quirks = 0,
+	.quirks = KVASER_USB_QUIRK_HAS_HARDWARE_TIMESTAMP,
 	.ops = &kvaser_usb_hydra_dev_ops,
 };
 
@@ -668,6 +668,14 @@ static const struct net_device_ops kvaser_usb_netdev_ops = {
 	.ndo_change_mtu = can_change_mtu,
 };
 
+static const struct net_device_ops kvaser_usb_netdev_ops_hwts = {
+	.ndo_open = kvaser_usb_open,
+	.ndo_stop = kvaser_usb_close,
+	.ndo_eth_ioctl = can_eth_ioctl_hwts,
+	.ndo_start_xmit = kvaser_usb_start_xmit,
+	.ndo_change_mtu = can_change_mtu,
+};
+
 static void kvaser_usb_get_drvinfo(struct net_device *netdev,
 				   struct ethtool_drvinfo *drvinfo)
 {
@@ -676,6 +684,12 @@ static void kvaser_usb_get_drvinfo(struct net_device *netdev,
 
 static const struct ethtool_ops kvaser_usb_ethtool_ops = {
 	.get_drvinfo = kvaser_usb_get_drvinfo,
+	.get_ts_info = ethtool_op_get_ts_info,
+};
+
+static const struct ethtool_ops kvaser_usb_ethtool_ops_hwts = {
+	.get_drvinfo = kvaser_usb_get_drvinfo,
+	.get_ts_info = can_ethtool_op_get_ts_info_hwts,
 };
 
 static void kvaser_usb_remove_interfaces(struct kvaser_usb *dev)
@@ -755,8 +769,13 @@ static int kvaser_usb_init_one(struct kvaser_usb *dev, int channel)
 	netdev->flags |= IFF_ECHO;
 
 	netdev->netdev_ops = &kvaser_usb_netdev_ops;
-	netdev->ethtool_ops = &kvaser_usb_ethtool_ops;
-
+	if (driver_info->quirks & KVASER_USB_QUIRK_HAS_HARDWARE_TIMESTAMP) {
+		netdev->netdev_ops = &kvaser_usb_netdev_ops_hwts;
+		netdev->ethtool_ops = &kvaser_usb_ethtool_ops_hwts;
+	} else {
+		netdev->netdev_ops = &kvaser_usb_netdev_ops;
+		netdev->ethtool_ops = &kvaser_usb_ethtool_ops;
+	}
 	SET_NETDEV_DEV(netdev, &dev->intf->dev);
 	netdev->dev_id = channel;
 
-- 
2.35.1