[PATCH v4 17/20] can: netlink: make can_tdc_fill_info() FD agnostic

[Vincent Mailhol <mailhol@kernel.org>]

can_tdc_fill_info() depends on some variables which are specific to CAN
FD. Move these to the function parameters list so that, later on, this
function can be reused for the CAN XL TDC.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
Changelog:

v1 -> v2:

  - Change WARN_ON(1) into return -EOPNOTSUPP to suppress a gcc
    warning.
    Link: https://lore.kernel.org/linux-can/202509050541.1FKRbqOi-lkp@intel.com/

RFC -> v1:

 - Just pass the IFLA index instead of passing each argument
   individually. Instead, derive these as local variables depending on
   whethe the IFLA index is IFLA_CAN_TDC or IFLA_CAN_XL_TDC.
---
 drivers/net/can/dev/netlink.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 9794f283ed588e37fbc9a189cb54c6965960d436..99038e0fb25f4e05cd181b188d5aeea25de8f77e 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -585,21 +585,34 @@ static int can_bitrate_const_fill_info(struct sk_buff *skb,
 			sizeof(*bitrate_const) * cnt, bitrate_const);
 }
 
-static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev)
+static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev,
+			     int ifla_can_tdc)
 {
-	struct nlattr *nest;
 	struct can_priv *priv = netdev_priv(dev);
-	struct can_tdc *tdc = &priv->fd.tdc;
-	const struct can_tdc_const *tdc_const = priv->fd.tdc_const;
+	struct data_bittiming_params *dbt_params;
+	const struct can_tdc_const *tdc_const;
+	struct can_tdc *tdc;
+	struct nlattr *nest;
+	bool tdc_is_enabled, tdc_manual;
+
+	if (ifla_can_tdc == IFLA_CAN_TDC) {
+		dbt_params = &priv->fd;
+		tdc_is_enabled = can_fd_tdc_is_enabled(priv);
+		tdc_manual = priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL;
+	} else {
+		return -EOPNOTSUPP; /* Place holder for CAN XL */
+	}
+	tdc_const = dbt_params->tdc_const;
+	tdc = &dbt_params->tdc;
 
 	if (!tdc_const)
 		return 0;
 
-	nest = nla_nest_start(skb, IFLA_CAN_TDC);
+	nest = nla_nest_start(skb, ifla_can_tdc);
 	if (!nest)
 		return -EMSGSIZE;
 
-	if (priv->ctrlmode_supported & CAN_CTRLMODE_TDC_MANUAL &&
+	if (tdc_manual &&
 	    (nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MIN, tdc_const->tdcv_min) ||
 	     nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MAX, tdc_const->tdcv_max)))
 		goto err_cancel;
@@ -611,15 +624,15 @@ static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	     nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MAX, tdc_const->tdcf_max)))
 		goto err_cancel;
 
-	if (can_fd_tdc_is_enabled(priv)) {
+	if (tdc_is_enabled) {
 		u32 tdcv;
 		int err = -EINVAL;
 
-		if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) {
+		if (tdc_manual) {
 			tdcv = tdc->tdcv;
 			err = 0;
-		} else if (priv->fd.do_get_auto_tdcv) {
-			err = priv->fd.do_get_auto_tdcv(dev, &tdcv);
+		} else if (dbt_params->do_get_auto_tdcv) {
+			err = dbt_params->do_get_auto_tdcv(dev, &tdcv);
 		}
 		if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv))
 			goto err_cancel;
@@ -707,7 +720,7 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 		     sizeof(priv->bitrate_max),
 		     &priv->bitrate_max)) ||
 
-	    can_tdc_fill_info(skb, dev) ||
+	    can_tdc_fill_info(skb, dev, IFLA_CAN_TDC) ||
 
 	    can_ctrlmode_ext_fill_info(skb, priv)
 	    )

-- 
2.49.1