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Commit 54472edf authored by Sekhar Nori's avatar Sekhar Nori Committed by David S. Miller
Browse files

drivers: net: davinci_mdio: prevent spurious timeout 



A well timed kernel preemption in the time_after() loop
in wait_for_idle() can result in a spurious timeout
error to be returned.

Fix it by using readl_poll_timeout() which takes care of
this issue.

Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarSekhar Nori <nsekhar@ti.com>
Reviewed-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bfe1e616

drivers/net/ethernet/ti/davinci_mdio.c

+8 −7
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <linux/clk.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/iopoll.h>

#include <linux/pm_runtime.h>

#include <linux/davinci_emac.h>

#include <linux/of.h>
@@ -227,14 +228,14 @@ static inline int wait_for_user_access(struct davinci_mdio_data *data) 
static inline int wait_for_idle(struct davinci_mdio_data *data)

{

	struct davinci_mdio_regs __iomem *regs = data->regs;

	unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);

	u32 val, ret;



	while (time_after(timeout, jiffies)) {

		if (__raw_readl(&regs->control) & CONTROL_IDLE)

			return 0;

	}

	ret = readl_poll_timeout(&regs->control, val, val & CONTROL_IDLE,

				 0, MDIO_TIMEOUT * 1000);

	if (ret)

		dev_err(data->dev, "timed out waiting for idle\n");

	return -ETIMEDOUT;



	return ret;

}



static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)