Commit e8060f08 authored by Vincent Mailhol's avatar Vincent Mailhol Committed by Marc Kleine-Budde
Browse files

can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device 

Some CAN device can measure the TDCV (Transmission Delay Compensation
Value) automatically for each transmitted CAN frames.

A callback function do_get_auto_tdcv() is added to retrieve that
value. This function is used only if CAN_CTRLMODE_TDC_AUTO is enabled
(if CAN_CTRLMODE_TDC_MANUAL is selected, the TDCV value is provided by
the user).

If the device does not support reporting of TDCV, do_get_auto_tdcv()
should be set to NULL and TDCV will not be reported by the netlink
interface.

On success, do_get_auto_tdcv() shall return 0. If the value can not be
measured by the device, for example because network is down or because
no frames were transmitted yet, can_priv::do_get_auto_tdcv() shall
return a negative error code (e.g. -EINVAL) to signify that the value
is not yet available. In such cases, TDCV is not reported by the
netlink interface.

Link: https://lore.kernel.org/all/20210918095637.20108-6-mailhol.vincent@wanadoo.fr


CC: Stefan Mätje <stefan.maetje@esd.eu>
Signed-off-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent d99755f7

drivers/net/can/dev/netlink.c

+12 −3
Original line number Diff line number Diff line
@@ -372,7 +372,8 @@ static size_t can_tdc_get_size(const struct net_device *dev) 
	}



	if (can_tdc_is_enabled(priv)) {

		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL)

		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL ||

		    priv->do_get_auto_tdcv)

			size += nla_total_size(sizeof(u32));	/* IFLA_CAN_TDCV */

		size += nla_total_size(sizeof(u32));		/* IFLA_CAN_TDCO */

		if (priv->tdc_const->tdcf_max)
@@ -445,8 +446,16 @@ static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev) 
		goto err_cancel;



	if (can_tdc_is_enabled(priv)) {

		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL &&

		    nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdc->tdcv))

		u32 tdcv;

		int err = -EINVAL;



		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) {

			tdcv = tdc->tdcv;

			err = 0;

		} else if (priv->do_get_auto_tdcv) {

			err = priv->do_get_auto_tdcv(dev, &tdcv);

		}

		if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv))

			goto err_cancel;

		if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO, tdc->tdco))

			goto err_cancel;

include/linux/can/dev.h

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ struct can_priv { 
			    enum can_state *state);

	int (*do_get_berr_counter)(const struct net_device *dev,

				   struct can_berr_counter *bec);

	int (*do_get_auto_tdcv)(const struct net_device *dev, u32 *tdcv);



	unsigned int echo_skb_max;

	struct sk_buff **echo_skb;