[PATCH v2 6/8] net: ti: icssg-ethtool: Adjust channel count for SR1.0

[Diogo Ivo]

SR1.0 uses the highest priority channel to transmit control
messages to the firmware. Take this into account when computing
channels.

Based on the work of Roger Quadros in TI's 5.10 SDK [1].

[1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/?h=ti-linux-5.10.y

Co-developed-by: Jan Kiszka <jan.kiszka at siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
Signed-off-by: Diogo Ivo <diogo.ivo at siemens.com>
---
 drivers/net/ethernet/ti/icssg/icssg_ethtool.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
index a27ec1dcc8d5..29e67526fa22 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
@@ -141,6 +141,9 @@ static int emac_set_channels(struct net_device *ndev,
 		return -EBUSY;
 
 	emac->tx_ch_num = ch->tx_count;
+	/* highest channel number for management messaging on SR1 */
+	if (emac->is_sr1)
+		emac->tx_ch_num++;
 
 	return 0;
 }
@@ -151,9 +154,12 @@ static void emac_get_channels(struct net_device *ndev,
 	struct prueth_emac *emac = netdev_priv(ndev);
 
 	ch->max_rx = 1;
-	ch->max_tx = PRUETH_MAX_TX_QUEUES;
+	/* SR1 use high priority channel for management messages */
+	ch->max_tx = emac->is_sr1 ? PRUETH_MAX_TX_QUEUES - 1 :
+				    PRUETH_MAX_TX_QUEUES;
 	ch->rx_count = 1;
-	ch->tx_count = emac->tx_ch_num;
+	ch->tx_count = emac->is_sr1 ? emac->tx_ch_num - 1 :
+				      emac->tx_ch_num;
 }
 
 static const struct ethtool_rmon_hist_range emac_rmon_ranges[] = {
-- 
2.43.0