Commit bc05a894 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: allow to change the device mtu for CAN FD capable devices 



The configuration for CAN FD depends on CAN_CTRLMODE_FD enabled in the driver
specific ctrlmode_supported capabilities.

The configuration can be done either with the 'fd { on | off }' option in the
'ip' tool from iproute2 or by setting the CAN netdevice MTU to CAN_MTU (16) or
to CANFD_MTU (72).

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Acked-by: default avatarStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 9859ccd2

drivers/net/can/dev.c

+39 −0
Original line number Diff line number Diff line
@@ -594,6 +594,39 @@ void free_candev(struct net_device *dev) 
}

EXPORT_SYMBOL_GPL(free_candev);



/*

 * changing MTU and control mode for CAN/CANFD devices

 */

int can_change_mtu(struct net_device *dev, int new_mtu)

{

	struct can_priv *priv = netdev_priv(dev);



	/* Do not allow changing the MTU while running */

	if (dev->flags & IFF_UP)

		return -EBUSY;



	/* allow change of MTU according to the CANFD ability of the device */

	switch (new_mtu) {

	case CAN_MTU:

		priv->ctrlmode &= ~CAN_CTRLMODE_FD;

		break;



	case CANFD_MTU:

		if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))

			return -EINVAL;



		priv->ctrlmode |= CAN_CTRLMODE_FD;

		break;



	default:

		return -EINVAL;

	}



	dev->mtu = new_mtu;

	return 0;

}

EXPORT_SYMBOL_GPL(can_change_mtu);



/*

 * Common open function when the device gets opened.

 *
@@ -693,6 +726,12 @@ static int can_changelink(struct net_device *dev, 
			return -EOPNOTSUPP;

		priv->ctrlmode &= ~cm->mask;

		priv->ctrlmode |= cm->flags;



		/* CAN_CTRLMODE_FD can only be set when driver supports FD */

		if (priv->ctrlmode & CAN_CTRLMODE_FD)

			dev->mtu = CANFD_MTU;

		else

			dev->mtu = CAN_MTU;

	}



	if (data[IFLA_CAN_RESTART_MS]) {

include/linux/can/dev.h

+1 −0
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ struct can_priv *safe_candev_priv(struct net_device *dev); 


int open_candev(struct net_device *dev);

void close_candev(struct net_device *dev);

int can_change_mtu(struct net_device *dev, int new_mtu);



int register_candev(struct net_device *dev);

void unregister_candev(struct net_device *dev);

include/uapi/linux/can/netlink.h

+1 −0
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ struct can_ctrlmode { 
#define CAN_CTRLMODE_3_SAMPLES		0x04	/* Triple sampling mode */

#define CAN_CTRLMODE_ONE_SHOT		0x08	/* One-Shot mode */

#define CAN_CTRLMODE_BERR_REPORTING	0x10	/* Bus-error reporting */

#define CAN_CTRLMODE_FD			0x20	/* CAN FD mode */



/*

 * CAN device statistics

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