[PATCH net-next v2 1/1] net: stmmac: check CBS input values before configuration

[Gan Yi Fang <yi.fang.gan@intel.com>]

From: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>

Add check for below conditions before proceeding to configuration.
A message will be prompted if the input value is invalid.

Idleslope minus sendslope should equal speed_div.
Idleslope is always a positive value including zero.
Sendslope is always a negative value including zero.
Hicredit is always a positive value including zero.
Locredit is always a negative value including zero.

Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: Gan, Yi Fang <yi.fang.gan@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index ac41ef4cbd2f..e8a079946f84 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -381,6 +381,11 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 		return -EOPNOTSUPP;
 	}
 
+	if ((qopt->idleslope - qopt->sendslope != speed_div) ||
+	    qopt->idleslope < 0 || qopt->sendslope > 0 ||
+	    qopt->hicredit < 0 || qopt->locredit > 0)
+		return -EINVAL;
+
 	mode_to_use = priv->plat->tx_queues_cfg[queue].mode_to_use;
 	if (mode_to_use == MTL_QUEUE_DCB && qopt->enable) {
 		ret = stmmac_dma_qmode(priv, priv->ioaddr, queue, MTL_QUEUE_AVB);
-- 
2.34.1