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: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
	
	
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					 3 changed files with 41 additions and 0 deletions
				
			
		|  | @ -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]) { | ||||
|  |  | |||
|  | @ -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); | ||||
|  |  | |||
|  | @ -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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	 Oliver Hartkopp
				Oliver Hartkopp