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From: <harinikatakamlinux@gmail.com>
To: <nicolas.ferre@atmel.com>, <davem@davemloft.net>,
	<harinikatakamlinux@gmail.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<harinik@xilinx.com>, <michals@xilinx.com>, <appanad@xilinx.com>,
	Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Subject: [RFC PATCH 1/5] net: macb: Check MDIO state before read/write and use timeouts
Date: Thu, 22 Mar 2018 19:21:36 +0530	[thread overview]
Message-ID: <1521726700-22634-2-git-send-email-harinikatakamlinux@gmail.com> (raw)
In-Reply-To: <1521726700-22634-1-git-send-email-harinikatakamlinux@gmail.com>

From: Harini Katakam <harinik@xilinx.com>

Replace the while loop in MDIO read/write functions with a timeout.
In addition, add a check for MDIO bus busy before initiating a new
operation as well to make sure there is no ongoing MDIO operation.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Harini Katakam <harinik@xilinx.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 54 ++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index d09bd43..f4030c1 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -321,6 +321,21 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 {
 	struct macb *bp = bus->priv;
 	int value;
+	ulong timeout;
+
+	timeout = jiffies + msecs_to_jiffies(1000);
+	/* wait for end of transfer */
+	do {
+		if (MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+			break;
+
+		cpu_relax();
+	} while (!time_after_eq(jiffies, timeout));
+
+	if (time_after_eq(jiffies, timeout)) {
+		netdev_err(bp->dev, "wait for end of transfer timed out\n");
+		return -ETIMEDOUT;
+	}
 
 	macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
 			      | MACB_BF(RW, MACB_MAN_READ)
@@ -328,9 +343,19 @@ static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 			      | MACB_BF(REGA, regnum)
 			      | MACB_BF(CODE, MACB_MAN_CODE)));
 
+	timeout = jiffies + msecs_to_jiffies(1000);
 	/* wait for end of transfer */
-	while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+	do {
+		if (MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+			break;
+
 		cpu_relax();
+	} while (!time_after_eq(jiffies, timeout));
+
+	if (time_after_eq(jiffies, timeout)) {
+		netdev_err(bp->dev, "wait for end of transfer timed out\n");
+		return -ETIMEDOUT;
+	}
 
 	value = MACB_BFEXT(DATA, macb_readl(bp, MAN));
 
@@ -341,6 +366,21 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 			   u16 value)
 {
 	struct macb *bp = bus->priv;
+	ulong timeout;
+
+	timeout = jiffies + msecs_to_jiffies(1000);
+	/* wait for end of transfer */
+	do {
+		if (MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+			break;
+
+		cpu_relax();
+	} while (!time_after_eq(jiffies, timeout));
+
+	if (time_after_eq(jiffies, timeout)) {
+		netdev_err(bp->dev, "wait for end of transfer timed out\n");
+		return -ETIMEDOUT;
+	}
 
 	macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
 			      | MACB_BF(RW, MACB_MAN_WRITE)
@@ -349,9 +389,19 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 			      | MACB_BF(CODE, MACB_MAN_CODE)
 			      | MACB_BF(DATA, value)));
 
+	timeout = jiffies + msecs_to_jiffies(1000);
 	/* wait for end of transfer */
-	while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+	do {
+		if (MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
+			break;
+
 		cpu_relax();
+	} while (!time_after_eq(jiffies, timeout));
+
+	if (time_after_eq(jiffies, timeout)) {
+		netdev_err(bp->dev, "wait for end of transfer timed out\n");
+		return -ETIMEDOUT;
+	}
 
 	return 0;
 }
-- 
2.7.4

  reply	other threads:[~2018-03-22 13:52 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-22 13:51 [RFC PATCH 0/5] Macb power management support for ZynqMP harinikatakamlinux
2018-03-22 13:51 ` harinikatakamlinux [this message]
2018-03-22 14:47   ` [RFC PATCH 1/5] net: macb: Check MDIO state before read/write and use timeouts Andrew Lunn
2018-05-03 10:08   ` Claudiu Beznea
2018-05-03 10:58     ` Harini Katakam
2018-03-22 13:51 ` [RFC PATCH 2/5] net: macb: Support clock management for tsu_clk harinikatakamlinux
2018-03-22 13:51 ` [RFC PATCH 3/5] net: macb: Add pm runtime support harinikatakamlinux
2018-05-03 10:09   ` Claudiu Beznea
2018-05-03 11:13     ` Harini Katakam
2018-05-03 12:59       ` Claudiu Beznea
2018-03-22 13:51 ` [RFC PATCH 4/5] net: macb: Add support for suspend/resume with full power down harinikatakamlinux
2018-05-03 10:09   ` Claudiu Beznea
2018-05-03 11:20     ` Harini Katakam
2018-05-03 12:23       ` Claudiu Beznea
2018-03-22 13:51 ` [RFC PATCH 5/5] net: macb: Add WOL support with ARP harinikatakamlinux
2018-05-04 12:17   ` Claudiu Beznea
2018-05-10 10:37     ` Harini Katakam
2018-05-15  8:39       ` Claudiu Beznea

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