On 6/28/2024 2:50 PM, Sagar Cheluvegowda wrote:

On 6/26/2024 7:58 AM, Andrew Halaney wrote:

quoted

On Tue, Jun 25, 2024 at 04:49:30PM GMT, Sagar Cheluvegowda wrote:

quoted

When mac link goes down we don't need to mainitain the clocks to operate
at higher frequencies, as an optimized solution to save power when
the link goes down we are trying to bring down the clocks to the
frequencies corresponding to the lowest speed possible.

Signed-off-by: Sagar Cheluvegowda <redacted>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index ec7c61ee44d4..f0166f0bc25f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -996,6 +996,9 @@ static void stmmac_mac_link_down(struct phylink_config *config,
 {
 	struct stmmac_priv *priv = netdev_priv(to_net_dev(config->dev));
 
+	if (priv->plat->fix_mac_speed)
+		priv->plat->fix_mac_speed(priv->plat->bsp_priv, SPEED_10, mode);
+

The above fix_mac_speed needs to be removed, i lately realized this mistake.

quoted

quoted

 	stmmac_mac_set(priv, priv->ioaddr, false);
 	priv->eee_active = false;
 	priv->tx_lpi_enabled = false;

@@ -1004,6 +1007,11 @@ static void stmmac_mac_link_down(struct phylink_config *config,
 
 	if (priv->dma_cap.fpesel)
 		stmmac_fpe_link_state_handle(priv, false);
+
+	stmmac_set_icc_bw(priv, SPEED_10);
+
+	if (priv->plat->fix_mac_speed)
+		priv->plat->fix_mac_speed(priv->plat->bsp_priv, SPEED_10, mode);

I think you're doing this at the beginning and end of
stmmac_mac_link_down(), is that intentional?

I realised that bringing down the clock to 10Mbps should be the last operation
of the link down process, the reason being if we bring down the clocks first it will
deprive essential internal clocks to DMA/MTL modules which are required for
Cleanup operations this might cause excessive delays in stopping DMA
or flusing MTL queues.
 

quoted