Re: Spurious timeouts in mvmdio

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On 12/04/2013 12:42 AM, Russell King - ARM Linux wrote:
This will make it correct when using interrupts but it will make the
loop wait one jiffie longer than it should when polling.

Alternatively, code it like this instead.

  drivers/net/ethernet/marvell/mvmdio.c |   32 +++++++++++++++-----------------
  1 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c
index 7354960b583b..a6f59831fc5b 100644
--- a/drivers/net/ethernet/marvell/mvmdio.c
+++ b/drivers/net/ethernet/marvell/mvmdio.c
@@ -76,31 +76,29 @@ static int orion_mdio_wait_ready(struct mii_bus *bus)
  {
  	struct orion_mdio_dev *dev = bus->priv;
  	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
-	unsigned long end = jiffies + timeout;
-	int timedout = 0;

-	while (1) {
-	        if (orion_mdio_smi_is_done(dev))
+	if (dev->err_interrupt > 0) {
+		if (wait_event_timeout(dev->smi_busy_wait,
+				       orion_mdio_smi_is_done(dev),
+				       1 + timeout))
  			return 0;
-	        else if (timedout)
-			break;
+	} else {
+		unsigned long end = jiffies + timeout;

-	        if (dev->err_interrupt <= 0) {
-			usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
-				     MVMDIO_SMI_POLL_INTERVAL_MAX);
+		while (1) {
+	        	if (orion_mdio_smi_is_done(dev))
+				return 0;

  			if (time_is_before_jiffies(end))
-				++timedout;
-	        } else {
-			wait_event_timeout(dev->smi_busy_wait,
-				           orion_mdio_smi_is_done(dev),
-				           timeout);
-
-			++timedout;
-	        }
+				break;
+
+			usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
+				     MVMDIO_SMI_POLL_INTERVAL_MAX);
+		}
  	}

  	dev_err(bus->parent, "Timeout: SMI busy for too long\n");
+
  	return  -ETIMEDOUT;
  }

Hi Russell,

I have just tested your patch on MV88F6281 and MV88F6282 both in polling and irq mode and it works just fine.

I had a similar patch almost ready to submit but you were faster than me.

Feel free to add my:

Tested-by: Nicolas Schichan <nschichan@xxxxxxxxxx>

Thanks,

--
Nicolas Schichan
Freebox SAS
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