netdev - [PATCH v4 net] net: stmmac: dwmac4: extend timeout for VLAN Tag register busy bit check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240924205424.573913-1-shenwei.wang@nxp.com>
Date: Tue, 24 Sep 2024 15:54:24 -0500
From: Shenwei Wang <shenwei.wang@....com>
To: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	horms@...nel.org
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Jose Abreu <joabreu@...opsys.com>,
	Ong Boon Leong <boon.leong.ong@...el.com>,
	Wong Vee Khee <vee.khee.wong@...el.com>,
	Chuah Kim Tatt <kim.tatt.chuah@...el.com>,
	netdev@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org,
	imx@...ts.linux.dev,
	linux-imx@....com,
	Serge Semin <fancer.lancer@...il.com>,
	Shenwei Wang <shenwei.wang@....com>,
	Andrew Lunn <andrew@...n.ch>
Subject: [PATCH v4 net] net: stmmac: dwmac4: extend timeout for VLAN Tag register busy bit check

Increase the timeout for checking the busy bit of the VLAN Tag register
from 10µs to 500ms. This change is necessary to accommodate scenarios
where Energy Efficient Ethernet (EEE) is enabled.

Overnight testing revealed that when EEE is active, the busy bit can
remain set for up to approximately 300ms. The new 500ms timeout provides
a safety margin.

Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering")
Reviewed-by: Andrew Lunn <andrew@...n.ch>
Signed-off-by: Shenwei Wang <shenwei.wang@....com>
---
Changes in V4:
 - fixed the comments and R-b.

Changes in V3:
 - re-org the error-check flow per Serge's review.

Changes in v2:
 - replace the udelay with readl_poll_timeout per Simon's review.

---
 .../net/ethernet/stmicro/stmmac/dwmac4_core.c  | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index a1858f083eef..e65a65666cc1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/ethtool.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include "stmmac.h"
 #include "stmmac_pcs.h"
 #include "dwmac4.h"
@@ -471,7 +472,7 @@ static int dwmac4_write_vlan_filter(struct net_device *dev,
 				    u8 index, u32 data)
 {
 	void __iomem *ioaddr = (void __iomem *)dev->base_addr;
-	int i, timeout = 10;
+	int ret;
 	u32 val;

 	if (index >= hw->num_vlan)
@@ -487,16 +488,15 @@ static int dwmac4_write_vlan_filter(struct net_device *dev,

 	writel(val, ioaddr + GMAC_VLAN_TAG);

-	for (i = 0; i < timeout; i++) {
-		val = readl(ioaddr + GMAC_VLAN_TAG);
-		if (!(val & GMAC_VLAN_TAG_CTRL_OB))
-			return 0;
-		udelay(1);
+	ret = readl_poll_timeout(ioaddr + GMAC_VLAN_TAG, val,
+				 !(val & GMAC_VLAN_TAG_CTRL_OB),
+				 1000, 500000);
+	if (ret) {
+		netdev_err(dev, "Timeout accessing MAC_VLAN_Tag_Filter\n");
+		return -EBUSY;
 	}

-	netdev_err(dev, "Timeout accessing MAC_VLAN_Tag_Filter\n");
-
-	return -EBUSY;
+	return 0;
 }

 static int dwmac4_add_hw_vlan_rx_fltr(struct net_device *dev,
--
2.34.1