Re: [PATCH RFC net-next v2 0/3] net: stmmac: approach 2 to solve EEE LPI reset issues

["Russell King (Oracle)" <linux@armlinux.org.uk>]

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On Fri, Mar 07, 2025 at 04:11:19PM +0000, Jon Hunter wrote:
> Hi Russell,
> 
> On 06/03/2025 15:23, Russell King (Oracle) wrote:
> > Hi,
> > 
> > This is a second approach to solving the STMMAC reset issues caused by
> > the lack of receive clock from the PHY where the media is in low power
> > mode with a PHY that supports receive clock-stop.
> > 
> > The first approach centred around only addressing the issue in the
> > resume path, but it seems to also happen when the platform glue module
> > is removed and re-inserted (Jon - can you check whether that's also
> > the case for you please?)
> > 
> > As this is more targetted, I've dropped the patches from this series
> > which move the call to phylink_resume(), so the link may still come
> > up too early on resume - but that's something I also intend to fix.
> > 
> > This is experimental - so I value test reports for this change.
> 
> 
> The subject indicates 3 patches, but I only see 2 patches? Can you confirm
> if there are 2 or 3?

Yes, 2 patches is correct.

> So far I have only tested to resume case with the 2 patches to make that
> that is working but on Tegra186, which has been the most problematic, it is
> not working reliably on top of next-20250305.

To confirm, you're seeing stmmac_reset() sporadically timing out on
resume even with these patches appled? That's rather disappointing.

Do either of the two attached diffs make any difference?

Thanks for testing!

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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[-- Attachment #2: stmmac-block-rx-clk-stop.diff --]
[-- Type: text/x-diff, Size: 1098 bytes --]

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8d3cae5b43c5..63d30e09c095 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3108,9 +3108,7 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 		priv->plat->dma_cfg->atds = 1;
 
 	/* Note that the PHY clock must be running for reset to complete. */
-	phylink_rx_clk_stop_block(priv->phylink);
 	ret = stmmac_reset(priv, priv->ioaddr);
-	phylink_rx_clk_stop_unblock(priv->phylink);
 	if (ret) {
 		netdev_err(priv->dev, "Failed to reset the dma\n");
 		return ret;
@@ -3480,7 +3478,9 @@ static int stmmac_hw_setup(struct net_device *dev, bool ptp_register)
 		phylink_pcs_pre_init(priv->phylink, priv->hw->phylink_pcs);
 
 	/* DMA initialization and SW reset */
+	phylink_rx_clk_stop_block(priv->phylink);
 	ret = stmmac_init_dma_engine(priv);
+	phylink_rx_clk_stop_unblock(priv->phylink);
 	if (ret < 0) {
 		netdev_err(priv->dev, "%s: DMA engine initialization failed\n",
 			   __func__);

[-- Attachment #3: stmmac-block-rx-clk-stop-2.diff --]
[-- Type: text/x-diff, Size: 1303 bytes --]

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8d3cae5b43c5..bebc9f98c875 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3108,9 +3108,7 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 		priv->plat->dma_cfg->atds = 1;
 
 	/* Note that the PHY clock must be running for reset to complete. */
-	phylink_rx_clk_stop_block(priv->phylink);
 	ret = stmmac_reset(priv, priv->ioaddr);
-	phylink_rx_clk_stop_unblock(priv->phylink);
 	if (ret) {
 		netdev_err(priv->dev, "Failed to reset the dma\n");
 		return ret;
@@ -4045,7 +4043,9 @@ static int __stmmac_open(struct net_device *dev,
 		}
 	}
 
+	phylink_rx_clk_stop_block(priv->phylink);
 	ret = stmmac_hw_setup(dev, true);
+	phylink_rx_clk_stop_unblock(priv->phylink);
 	if (ret < 0) {
 		netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
 		goto init_error;
@@ -7949,7 +7949,9 @@ int stmmac_resume(struct device *dev)
 	stmmac_free_tx_skbufs(priv);
 	stmmac_clear_descriptors(priv, &priv->dma_conf);
 
+	phylink_rx_clk_stop_block(priv->phylink);
 	stmmac_hw_setup(ndev, false);
+	phylink_rx_clk_stop_unblock(priv->phylink);
 	stmmac_init_coalesce(priv);
 	stmmac_set_rx_mode(ndev);