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-rw-r--r--drivers/net/can/dev.c39
-rw-r--r--include/linux/can/dev.h1
-rw-r--r--include/uapi/linux/can/netlink.h1
3 files changed, 41 insertions, 0 deletions
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 8ebe112458c4..4e20d82b799e 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -595,6 +595,39 @@ 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.
*
* This function should be called in the open function of the device
@@ -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]) {
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 8adaee96f292..3ce5e526525f 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -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);
diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h
index b41933d6bdcd..7e2e1863db16 100644
--- a/include/uapi/linux/can/netlink.h
+++ b/include/uapi/linux/can/netlink.h
@@ -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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