[PATCH v5 6/7] can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device
From: Vincent Mailhol <hidden>
Date: 2021-08-15 03:34:21
Also in:
linux-can, lkml
Subsystem:
can network drivers, the rest · Maintainers:
Marc Kleine-Budde, Vincent Mailhol, Linus Torvalds
Some CAN device can measure the TDCV (Transmission Delay Compensation Value) automatically for each transmitted CAN frames. A callback function do_get_auto_tdcv() is added to retrieve that value. This function is used only if CAN_CTRLMODE_TDC_AUTO is enabled (if CAN_CTRLMODE_TDC_MANUAL is selected, the TDCV value is provided by the user). If the device does not support reporting of TDCV, do_get_auto_tdcv() should be set to NULL and TDCV will not be reported by the netlink interface. On success, do_get_auto_tdcv() shall return 0. If the value can not be measured by the device, for example because network is down or because no frames were transmitted yet, can_priv::do_get_auto_tdcv() shall return a negative error code (e.g. -EINVAL) to signify that the value is not yet available. In such cases, TDCV is not reported by the netlink interface. CC: Stefan Mätje <stefan.maetje@esd.eu> Signed-off-by: Vincent Mailhol <redacted> --- drivers/net/can/dev/netlink.c | 15 ++++++++++++--- include/linux/can/dev.h | 1 + 2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index f05745c96b9c..776284593b5d 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c@@ -362,7 +362,8 @@ static size_t can_tdc_get_size(const struct net_device *dev) } if (can_tdc_is_enabled(priv)) { - if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL || + priv->do_get_auto_tdcv) size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV */ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO */ if (priv->tdc_const->tdcf_max)
@@ -435,8 +436,16 @@ static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev) goto err_cancel; if (can_tdc_is_enabled(priv)) { - if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL && - nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdc->tdcv)) + u32 tdcv; + int err = -EINVAL; + + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) { + tdcv = tdc->tdcv; + err = 0; + } else if (priv->do_get_auto_tdcv) { + err = priv->do_get_auto_tdcv(dev, &tdcv); + } + if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv)) goto err_cancel; if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO, tdc->tdco)) goto err_cancel;
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index fa75e29182a3..266d0fe9de9d 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h@@ -74,6 +74,7 @@ struct can_priv { enum can_state *state); int (*do_get_berr_counter)(const struct net_device *dev, struct can_berr_counter *bec); + int (*do_get_auto_tdcv)(const struct net_device *dev, u32 *tdcv); unsigned int echo_skb_max; struct sk_buff **echo_skb;
--
2.31.1