| Message ID | 1515581725-29242-2-git-send-email-faiz_abbas@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/10/2018 11:55 AM, Faiz Abbas wrote: > From: Franklin S Cooper Jr <fcooper@ti.com> > > Various CAN or CAN-FD IP may be able to run at a faster rate than > what the transceiver the CAN node is connected to. This can lead to > unexpected errors. However, CAN transceivers typically have fixed > limitations and provide no means to discover these limitations at > runtime. Therefore, add support for a can-transceiver node that > can be reused by other CAN peripheral drivers to determine for both > CAN and CAN-FD what the max bitrate that can be used. If the user > tries to configure CAN to pass these maximum bitrates it will throw > an error. > > Also add support for reading bitrate_max via the netlink interface. added to can-next with some minor changes. See inline. > Reviewed-by: Suman Anna <s-anna@ti.com> > Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com> > [nsekhar@ti.com: fix build error with !CONFIG_OF] > Signed-off-by: Sekhar Nori <nsekhar@ti.com> > Signed-off-by: Faiz Abbas <faiz_abbas@ti.com> > --- > drivers/net/can/dev.c | 45 +++++++++++++++++++++++++++++++++++++++- > include/linux/can/dev.h | 8 +++++++ > include/uapi/linux/can/netlink.h | 1 + > 3 files changed, 53 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c > index 365a8cc..c5bc33f 100644 > --- a/drivers/net/can/dev.c > +++ b/drivers/net/can/dev.c > @@ -27,6 +27,7 @@ > #include <linux/can/skb.h> > #include <linux/can/netlink.h> > #include <linux/can/led.h> > +#include <linux/of.h> > #include <net/rtnetlink.h> > > #define MOD_DESC "CAN device driver interface" > @@ -814,6 +815,29 @@ int open_candev(struct net_device *dev) > } > EXPORT_SYMBOL_GPL(open_candev); > > +#ifdef CONFIG_OF > +/* Common function that can be used to understand the limitation of > + * a transceiver when it provides no means to determine these limitations > + * at runtime. > + */ > +void of_can_transceiver(struct net_device *dev) > +{ > + struct device_node *dn; > + struct can_priv *priv = netdev_priv(dev); > + struct device_node *np = dev->dev.parent->of_node; > + int ret; > + > + dn = of_get_child_by_name(np, "can-transceiver"); > + if (!dn) > + return; > + > + ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max); > + if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max)) > + netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n"); > +} > +EXPORT_SYMBOL_GPL(of_can_transceiver); > +#endif > + > /* > * Common close function for cleanup before the device gets closed. > * > @@ -913,6 +937,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], > priv->bitrate_const_cnt); > if (err) > return err; > + > + if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) { > + netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n", > + priv->bitrate_max); > + return -EINVAL; > + } > + > memcpy(&priv->bittiming, &bt, sizeof(bt)); > > if (priv->do_set_bittiming) { > @@ -997,6 +1028,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], > priv->data_bitrate_const_cnt); > if (err) > return err; > + > + if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) { > + netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n", > + priv->bitrate_max); > + return -EINVAL; > + } > + > memcpy(&priv->data_bittiming, &dbt, sizeof(dbt)); > > if (priv->do_set_data_bittiming) { > @@ -1064,6 +1102,7 @@ static size_t can_get_size(const struct net_device *dev) > if (priv->data_bitrate_const) /* IFLA_CAN_DATA_BITRATE_CONST */ > size += nla_total_size(sizeof(*priv->data_bitrate_const) * > priv->data_bitrate_const_cnt); > + size += sizeof(priv->bitrate_max); Added "mising" comment: /* IFLA_CAN_BITRATE_MAX */ > > return size; > } > @@ -1121,7 +1160,11 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev) > nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST, > sizeof(*priv->data_bitrate_const) * > priv->data_bitrate_const_cnt, > - priv->data_bitrate_const)) > + priv->data_bitrate_const)) || > + > + (nla_put(skb, IFLA_CAN_BITRATE_MAX, > + sizeof(priv->bitrate_max), > + &priv->bitrate_max)) > ) > > return -EMSGSIZE; > diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h > index 61f1cf2..a199423 100644 > --- a/include/linux/can/dev.h > +++ b/include/linux/can/dev.h > @@ -46,8 +46,10 @@ struct can_priv { > unsigned int bitrate_const_cnt; > const u32 *data_bitrate_const; > unsigned int data_bitrate_const_cnt; > + u32 bitrate_max; > struct can_clock clock; > > + I've removed this. > enum can_state state; > > /* CAN controller features - see include/uapi/linux/can/netlink.h */ > @@ -166,6 +168,12 @@ void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, > unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx); > void can_free_echo_skb(struct net_device *dev, unsigned int idx); > > +#ifdef CONFIG_OF > +void of_can_transceiver(struct net_device *dev); > +#else > +static inline void of_can_transceiver(struct net_device *dev) { } > +#endif > + > struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf); > struct sk_buff *alloc_canfd_skb(struct net_device *dev, > struct canfd_frame **cfd); > diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h > index 96710e7..9f56fad4 100644 > --- a/include/uapi/linux/can/netlink.h > +++ b/include/uapi/linux/can/netlink.h > @@ -132,6 +132,7 @@ enum { > IFLA_CAN_TERMINATION_CONST, > IFLA_CAN_BITRATE_CONST, > IFLA_CAN_DATA_BITRATE_CONST, > + IFLA_CAN_BITRATE_MAX, > __IFLA_CAN_MAX > }; > > Marc
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 365a8cc..c5bc33f 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -27,6 +27,7 @@ #include <linux/can/skb.h> #include <linux/can/netlink.h> #include <linux/can/led.h> +#include <linux/of.h> #include <net/rtnetlink.h> #define MOD_DESC "CAN device driver interface" @@ -814,6 +815,29 @@ int open_candev(struct net_device *dev) } EXPORT_SYMBOL_GPL(open_candev); +#ifdef CONFIG_OF +/* Common function that can be used to understand the limitation of + * a transceiver when it provides no means to determine these limitations + * at runtime. + */ +void of_can_transceiver(struct net_device *dev) +{ + struct device_node *dn; + struct can_priv *priv = netdev_priv(dev); + struct device_node *np = dev->dev.parent->of_node; + int ret; + + dn = of_get_child_by_name(np, "can-transceiver"); + if (!dn) + return; + + ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max); + if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max)) + netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n"); +} +EXPORT_SYMBOL_GPL(of_can_transceiver); +#endif + /* * Common close function for cleanup before the device gets closed. * @@ -913,6 +937,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], priv->bitrate_const_cnt); if (err) return err; + + if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) { + netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n", + priv->bitrate_max); + return -EINVAL; + } + memcpy(&priv->bittiming, &bt, sizeof(bt)); if (priv->do_set_bittiming) { @@ -997,6 +1028,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], priv->data_bitrate_const_cnt); if (err) return err; + + if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) { + netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n", + priv->bitrate_max); + return -EINVAL; + } + memcpy(&priv->data_bittiming, &dbt, sizeof(dbt)); if (priv->do_set_data_bittiming) { @@ -1064,6 +1102,7 @@ static size_t can_get_size(const struct net_device *dev) if (priv->data_bitrate_const) /* IFLA_CAN_DATA_BITRATE_CONST */ size += nla_total_size(sizeof(*priv->data_bitrate_const) * priv->data_bitrate_const_cnt); + size += sizeof(priv->bitrate_max); return size; } @@ -1121,7 +1160,11 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev) nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST, sizeof(*priv->data_bitrate_const) * priv->data_bitrate_const_cnt, - priv->data_bitrate_const)) + priv->data_bitrate_const)) || + + (nla_put(skb, IFLA_CAN_BITRATE_MAX, + sizeof(priv->bitrate_max), + &priv->bitrate_max)) ) return -EMSGSIZE; diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 61f1cf2..a199423 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -46,8 +46,10 @@ struct can_priv { unsigned int bitrate_const_cnt; const u32 *data_bitrate_const; unsigned int data_bitrate_const_cnt; + u32 bitrate_max; struct can_clock clock; + enum can_state state; /* CAN controller features - see include/uapi/linux/can/netlink.h */ @@ -166,6 +168,12 @@ void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx); void can_free_echo_skb(struct net_device *dev, unsigned int idx); +#ifdef CONFIG_OF +void of_can_transceiver(struct net_device *dev); +#else +static inline void of_can_transceiver(struct net_device *dev) { } +#endif + struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf); struct sk_buff *alloc_canfd_skb(struct net_device *dev, struct canfd_frame **cfd); diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h index 96710e7..9f56fad4 100644 --- a/include/uapi/linux/can/netlink.h +++ b/include/uapi/linux/can/netlink.h @@ -132,6 +132,7 @@ enum { IFLA_CAN_TERMINATION_CONST, IFLA_CAN_BITRATE_CONST, IFLA_CAN_DATA_BITRATE_CONST, + IFLA_CAN_BITRATE_MAX, __IFLA_CAN_MAX };