[PATCH net v2] net: phy: marvell10g: fix 88x3310 power up

[PATCH net v2] net: phy: marvell10g: fix 88x3310 power up

[Jiawen Wu]

Clear MV_V2_PORT_CTRL_PWRDOWN bit to set power up for 88x3310 PHY,
it sometimes does not take effect immediately. And a read of this
register causes the bit not to clear. This will cause mv3310_reset()
to time out, which will fail the config initialization. So add a delay
before the next access.

Fixes: c9cc1c815d36 ("net: phy: marvell10g: place in powersave mode at probe")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
---
v1 -> v2:
- change poll-bit-clear to time delay
---
 drivers/net/phy/marvell10g.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c
index 55d9d7acc32e..d4bb90d76881 100644
--- a/drivers/net/phy/marvell10g.c
+++ b/drivers/net/phy/marvell10g.c
@@ -328,6 +328,13 @@ static int mv3310_power_up(struct phy_device *phydev)
 	ret = phy_clear_bits_mmd(phydev, MDIO_MMD_VEND2, MV_V2_PORT_CTRL,
 				 MV_V2_PORT_CTRL_PWRDOWN);
 
+	/* Sometimes, the power down bit doesn't clear immediately, and
+	 * a read of this register causes the bit not to clear. Delay
+	 * 100us to allow the PHY to come out of power down mode before
+	 * the next access.
+	 */
+	udelay(100);
+
 	if (phydev->drv->phy_id != MARVELL_PHY_ID_88X3310 ||
 	    priv->firmware_ver < 0x00030000)
 		return ret;
-- 
2.27.0

Re: [PATCH net v2] net: phy: marvell10g: fix 88x3310 power up

[Russell King (Oracle)]

On Wed, Jul 19, 2023 at 05:22:33PM +0800, Jiawen Wu wrote:
> Clear MV_V2_PORT_CTRL_PWRDOWN bit to set power up for 88x3310 PHY,
> it sometimes does not take effect immediately. And a read of this
> register causes the bit not to clear. This will cause mv3310_reset()
> to time out, which will fail the config initialization. So add a delay
> before the next access.
> 
> Fixes: c9cc1c815d36 ("net: phy: marvell10g: place in powersave mode at probe")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

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Re: [PATCH net v2] net: phy: marvell10g: fix 88x3310 power up

[Paolo Abeni]

On Wed, 2023-07-19 at 17:22 +0800, Jiawen Wu wrote:
> Clear MV_V2_PORT_CTRL_PWRDOWN bit to set power up for 88x3310 PHY,
> it sometimes does not take effect immediately. And a read of this
> register causes the bit not to clear. This will cause mv3310_reset()
> to time out, which will fail the config initialization. So add a delay
> before the next access.
> 
> Fixes: c9cc1c815d36 ("net: phy: marvell10g: place in powersave mode at probe")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> ---
> v1 -> v2:
> - change poll-bit-clear to time delay
> ---
>  drivers/net/phy/marvell10g.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c
> index 55d9d7acc32e..d4bb90d76881 100644
> --- a/drivers/net/phy/marvell10g.c
> +++ b/drivers/net/phy/marvell10g.c
> @@ -328,6 +328,13 @@ static int mv3310_power_up(struct phy_device *phydev)
>  	ret = phy_clear_bits_mmd(phydev, MDIO_MMD_VEND2, MV_V2_PORT_CTRL,
>  				 MV_V2_PORT_CTRL_PWRDOWN);
>  
> +	/* Sometimes, the power down bit doesn't clear immediately, and
> +	 * a read of this register causes the bit not to clear. Delay
> +	 * 100us to allow the PHY to come out of power down mode before
> +	 * the next access.
> +	 */
> +	udelay(100);

Out of sheer ignorance, would an usleep_range(...) be more appropriate
here?

Thanks!

Paolo

Re: [PATCH net v2] net: phy: marvell10g: fix 88x3310 power up

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Wed, 19 Jul 2023 17:22:33 +0800 you wrote:
> Clear MV_V2_PORT_CTRL_PWRDOWN bit to set power up for 88x3310 PHY,
> it sometimes does not take effect immediately. And a read of this
> register causes the bit not to clear. This will cause mv3310_reset()
> to time out, which will fail the config initialization. So add a delay
> before the next access.
> 
> Fixes: c9cc1c815d36 ("net: phy: marvell10g: place in powersave mode at probe")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> 
> [...]

Here is the summary with links:
  - [net,v2] net: phy: marvell10g: fix 88x3310 power up
    https://git.kernel.org/netdev/net/c/c7b75bea853d

You are awesome, thank you!
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