[PATCH net-next v2 1/2] net: stmmac: Introduce a helper to check RSS support

[Maxime Chevallier]

The RSS feature is only available in stmmac if the hardware reports it
through the DMA caps and if the platform glue sets rss_en.

Introduce a helper that checks both.

For now, no platform sets rss_en, but there's interest in the topic so
leave the door open instead of dropping the feature altogether.

No functional changes intended.

Suggested-by: Nicolai Buchwitz <nb at tipi-net.de>
Signed-off-by: Maxime Chevallier <maxime.chevallier at bootlin.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      | 5 +++++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 7582fca63741..e2873d46e049 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -433,6 +433,11 @@ struct timespec64 stmmac_calc_tas_basetime(ktime_t old_base_time,
 					   ktime_t current_time,
 					   u64 cycle_time);
 
+static inline bool stmmac_rss_is_supported(const struct stmmac_priv *priv)
+{
+	return priv->dma_cap.rssen && priv->plat->rss_en;
+}
+
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,
 			 struct ethtool_test *etest, u64 *buf);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 4dee3542df3b..08feb18d62ba 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3538,7 +3538,7 @@ static void stmmac_mac_config_rx_queues_routing(struct stmmac_priv *priv)
 
 static void stmmac_mac_config_rss(struct stmmac_priv *priv)
 {
-	if (!priv->dma_cap.rssen || !priv->plat->rss_en) {
+	if (!stmmac_rss_is_supported(priv)) {
 		priv->rss.enable = false;
 		return;
 	}
@@ -8037,7 +8037,7 @@ static int __stmmac_dvr_probe(struct device *device,
 	for (i = 0; i < ARRAY_SIZE(priv->rss.table); i++)
 		priv->rss.table[i] = ethtool_rxfh_indir_default(i, rxq);
 
-	if (priv->dma_cap.rssen && priv->plat->rss_en)
+	if (stmmac_rss_is_supported(priv))
 		ndev->features |= NETIF_F_RXHASH;
 
 	ndev->vlan_features |= ndev->features;
-- 
2.55.0