netdev - [PATCH 6/6] stmmac: Replace infinite loops by timeouts in mdio r/w

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

Message-ID: <1330692928-30330-7-git-send-email-deepak.sikri@st.com>
Date:	Fri, 2 Mar 2012 18:25:28 +0530
From:	Deepak Sikri <deepak.sikri@...com>
To:	<peppe.cavallaro@...com>
Cc:	<spear-devel@...t.st.com>, <netdev@...r.kernel.org>,
	Deepak Sikri <deepak.sikri@...com>
Subject: [PATCH 6/6] stmmac: Replace infinite loops by timeouts in mdio r/w

This patch removes the infinite waits from the mdio read and
write interfaces. These infinite waits have been replaced by
the timeout handling. In case if a time out occurs, an error is
returned.

Signed-off-by: Deepak Sikri <deepak.sikri@...com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c |   30 ++++++++++++++++-----
 1 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index 7319532..b6a6fb2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -34,6 +34,20 @@
 #define MII_BUSY 0x00000001
 #define MII_WRITE 0x00000002
 
+static int stmmac_mdio_busy_wait(unsigned long ioaddr, unsigned int mii_addr)
+{
+	unsigned long finish = jiffies + 3 * HZ;
+
+	do {
+		if (readl(ioaddr + mii_addr) & MII_BUSY)
+			cpu_relax();
+		else
+			return 0;
+	} while (!time_after_eq(jiffies, finish));
+
+	return -EBUSY;
+}
+
 /**
  * stmmac_mdio_read
  * @bus: points to the mii_bus structure
@@ -56,9 +70,13 @@ static int stmmac_mdio_read(struct mii_bus *bus, int phyaddr, int phyreg)
 			((phyreg << 6) & (0x000007C0)));
 	regValue |= MII_BUSY | ((priv->plat->clk_csr & 7) << 2);
 
-	do {} while (((readl(priv->ioaddr + mii_address)) & MII_BUSY) == 1);
+	if (stmmac_mdio_busy_wait(priv->ioaddr, mii_address))
+		return -EBUSY;
+
 	writel(regValue, priv->ioaddr + mii_address);
-	do {} while (((readl(priv->ioaddr + mii_address)) & MII_BUSY) == 1);
+
+	if (stmmac_mdio_busy_wait(priv->ioaddr, mii_address))
+		return -EBUSY;
 
 	/* Read the data from the MII data register */
 	data = (int)readl(priv->ioaddr + mii_data);
@@ -88,18 +106,16 @@ static int stmmac_mdio_write(struct mii_bus *bus, int phyaddr, int phyreg,
 
 	value |= MII_BUSY | ((priv->plat->clk_csr & 7) << 2);
 
-
 	/* Wait until any existing MII operation is complete */
-	do {} while (((readl(priv->ioaddr + mii_address)) & MII_BUSY) == 1);
+	if (stmmac_mdio_busy_wait(priv->ioaddr, mii_address))
+		return -EBUSY;
 
 	/* Set the MII address register to write */
 	writel(phydata, priv->ioaddr + mii_data);
 	writel(value, priv->ioaddr + mii_address);
 
 	/* Wait until any existing MII operation is complete */
-	do {} while (((readl(priv->ioaddr + mii_address)) & MII_BUSY) == 1);
-
-	return 0;
+	return stmmac_mdio_busy_wait(priv->ioaddr, mii_address);
 }
 
 /**
-- 
1.6.0.2

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html