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Message-ID: <1521726700-22634-2-git-send-email-harinikatakamlinux@gmail.com>
Date: Thu, 22 Mar 2018 19:21:36 +0530
From: <harinikatakamlinux@...il.com>
To: <nicolas.ferre@...el.com>, <davem@...emloft.net>,
<harinikatakamlinux@...il.com>
CC: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<harinik@...inx.com>, <michals@...inx.com>, <appanad@...inx.com>,
Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>
Subject: [RFC PATCH 1/5] net: macb: Check MDIO state before read/write and use timeouts
From: Harini Katakam <harinik@...inx.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@...inx.com>
Signed-off-by: Harini Katakam <harinik@...inx.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
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