From bb208f144cf3f59d8f89a09a80efd04389718907 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Mon, 21 Mar 2016 20:18:21 +0100 Subject: can: fix handling of unmodifiable configuration options As described in 'can: m_can: tag current CAN FD controllers as non-ISO' (6cfda7fbebe) it is possible to define fixed configuration options by setting the according bit in 'ctrlmode' and clear it in 'ctrlmode_supported'. This leads to the incovenience that the fixed configuration bits can not be passed by netlink even when they have the correct values (e.g. non-ISO, FD). This patch fixes that issue and not only allows fixed set bit values to be set again but now requires(!) to provide these fixed values at configuration time. A valid CAN FD configuration consists of a nominal/arbitration bittiming, a data bittiming and a control mode with CAN_CTRLMODE_FD set - which is now enforced by a new can_validate() function. This fix additionally removed the inconsistency that was prohibiting the support of 'CANFD-only' controller drivers, like the RCar CAN FD. For this reason a new helper can_set_static_ctrlmode() has been introduced to provide a proper interface to handle static enabled CAN controller options. Reported-by: Ramesh Shanmugasundaram Signed-off-by: Oliver Hartkopp Reviewed-by: Ramesh Shanmugasundaram Cc: # >= 3.18 Signed-off-by: Marc Kleine-Budde --- include/linux/can/dev.h | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) (limited to 'include/linux/can/dev.h') diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 735f9f8c4e43..5261751f6bd4 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -40,8 +40,11 @@ struct can_priv { struct can_clock clock; enum can_state state; - u32 ctrlmode; - u32 ctrlmode_supported; + + /* CAN controller features - see include/uapi/linux/can/netlink.h */ + u32 ctrlmode; /* current options setting */ + u32 ctrlmode_supported; /* options that can be modified by netlink */ + u32 ctrlmode_static; /* static enabled options for driver/hardware */ int restart_ms; struct timer_list restart_timer; @@ -108,6 +111,21 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb) return skb->len == CANFD_MTU; } +/* helper to define static CAN controller features at device creation time */ +static inline void can_set_static_ctrlmode(struct net_device *dev, + u32 static_mode) +{ + struct can_priv *priv = netdev_priv(dev); + + /* alloc_candev() succeeded => netdev_priv() is valid at this point */ + priv->ctrlmode = static_mode; + priv->ctrlmode_static = static_mode; + + /* override MTU which was set by default in can_setup()? */ + if (static_mode & CAN_CTRLMODE_FD) + dev->mtu = CANFD_MTU; +} + /* get data length from can_dlc with sanitized can_dlc */ u8 can_dlc2len(u8 can_dlc); -- cgit