[PATCH net] net: enetc: correct the indexes of highest and 2nd highest TCs

[wei . fang]

From: Wei Fang <wei.fang@xxxxxxx>

For ENETC hardware, the TCs are numbered from 0 to N-1, where N
is the number of TCs. Numerically higher TC has higher priority.
It's obvious that the highest priority TC index should be N-1 and
the 2nd highest priority TC index should be N-2.
However, the previous logic uses netdev_get_prio_tc_map() to get
the indexes of highest priority and 2nd highest priority TCs, it
does not make sense and is incorrect. It may get wrong indexes of
the two TCs and make the CBS unconfigurable. e.g.
$ tc qdisc add dev eno0 parent root handle 100: mqprio num_tc 6 \
	map 0 0 1 1 2 3 4 5 queues 1@0 1@1 1@2 1@3 2@4 2@6 hw 1
$ tc qdisc replace dev eno0 parent 100:6 cbs idleslope 100000 \
	sendslope -900000 hicredit 12 locredit -113 offload 1
$ Error: Specified device failed to setup cbs hardware offload.
  ^^^^^

Fixes: c431047c4efe ("enetc: add support Credit Based Shaper(CBS) for hardware offload")
Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
---
 drivers/net/ethernet/freescale/enetc/enetc_qos.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_qos.c b/drivers/net/ethernet/freescale/enetc/enetc_qos.c
index 83c27bbbc6ed..126007ab70f6 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_qos.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_qos.c
@@ -181,8 +181,8 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 	int bw_sum = 0;
 	u8 bw;
 
-	prio_top = netdev_get_prio_tc_map(ndev, tc_nums - 1);
-	prio_next = netdev_get_prio_tc_map(ndev, tc_nums - 2);
+	prio_top = tc_nums - 1;
+	prio_next = tc_nums - 2;
 
 	/* Support highest prio and second prio tc in cbs mode */
 	if (tc != prio_top && tc != prio_next)
-- 
2.25.1