Re: [PATCH 6/7] net: phy: at803x: add disable hibernation mode support

[Marco Felsch <m.felsch@pengutronix.de>]

On 23-07-10, Ahmad Fatoum wrote:
> On 10.07.23 08:36, Marco Felsch wrote:
> > This commit ports Linux commit:
> > 
> > | commit 9ecf04016c87bcb33b44e24489d33618e2592f41
> > | Author: Wei Fang <wei.fang@nxp.com>
> > | Date:   Thu Aug 18 11:00:54 2022 +0800
> > |
> > |     net: phy: at803x: add disable hibernation mode support
> > |
> > |     When the cable is unplugged, the Atheros AR803x PHYs will enter
> > |     hibernation mode after about 10 seconds if the hibernation mode
> > |     is enabled and will not provide any clock to the MAC. But for
> > |     some MACs, this feature might cause unexpected issues due to the
> > |     logic of MACs.
> > |     Taking SYNP MAC (stmmac) as an example, if the cable is unplugged
> > |     and the "eth0" interface is down, the AR803x PHY will enter
> > |     hibernation mode. Then perform the "ifconfig eth0 up" operation,
> > |     the stmmac can't be able to complete the software reset operation
> > |     and fail to init it's own DMA. Therefore, the "eth0" interface is
> > |     failed to ifconfig up. Why does it cause this issue? The truth is
> > |     that the software reset operation of the stmmac is designed to
> > |     depend on the RX_CLK of PHY.
> > |     So, this patch offers an option for the user to determine whether
> > |     to disable the hibernation mode of AR803x PHYs.
> > |
> > |     Signed-off-by: Wei Fang <wei.fang@nxp.com>
> > |     Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> > |     Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> > 
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> 
> IMO we should just makes AT803X_DISABLE_HIBERNATION_MODE the default and
> never hibernate the PHY. Let Linux worry about that.

Got your point and I'm not sure. At least for drivers I like the sources
to bin in sync with Linux which allows porting fixes/features more
easily. Also since the API (dt-bindings) are there, so why not just
copy'n'paste from Linux?

Regards,
  Marco

> > ---
> >  drivers/net/phy/at803x.c | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> > 
> > diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
> > index cc425c318f..d8a9c3588f 100644
> > --- a/drivers/net/phy/at803x.c
> > +++ b/drivers/net/phy/at803x.c
> > @@ -32,6 +32,9 @@
> >  #define AT803X_DEBUG_REG_5			0x05
> >  #define AT803X_DEBUG_TX_CLK_DLY_EN		BIT(8)
> >  
> > +#define AT803X_DEBUG_REG_HIB_CTRL		0x0b
> > +#define   AT803X_DEBUG_HIB_CTRL_PS_HIB_EN	BIT(15)
> > +
> >  /* AT803x supports either the XTAL input pad, an internal PLL or the
> >   * DSP as clock reference for the clock output pad. The XTAL reference
> >   * is only used for 25 MHz output, all other frequencies need the PLL.
> > @@ -140,6 +143,20 @@ static int at803x_disable_tx_delay(struct phy_device *phydev)
> >  				     AT803X_DEBUG_TX_CLK_DLY_EN, 0);
> >  }
> >  
> > +static int at803x_hibernation_mode_config(struct phy_device *phydev)
> > +{
> > +	struct at803x_priv *priv = phydev->priv;
> > +
> > +	/* The default after hardware reset is hibernation mode enabled. After
> > +	 * software reset, the value is retained.
> > +	 */
> > +	if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE))
> > +		return 0;
> > +
> > +	return at803x_debug_reg_mask(phydev, AT803X_DEBUG_REG_HIB_CTRL,
> > +				     AT803X_DEBUG_HIB_CTRL_PS_HIB_EN, 0);
> > +}
> > +
> >  static bool at803x_match_phy_id(struct phy_device *phydev, u32 phy_id)
> >  {
> >  	struct phy_driver *drv = to_phy_driver(phydev->dev.driver);
> > @@ -160,6 +177,9 @@ static int at803x_parse_dt(struct phy_device *phydev)
> >  	if (of_property_read_bool(node, "qca,disable-smarteee"))
> >  		priv->flags |= AT803X_DISABLE_SMARTEEE;
> >  
> > +	if (of_property_read_bool(node, "qca,disable-hibernation-mode"))
> > +		priv->flags |= AT803X_DISABLE_HIBERNATION_MODE;
> > +
> >  	if (!of_property_read_u32(node, "qca,smarteee-tw-us-1g", &tw)) {
> >  		if (!tw || tw > 255) {
> >  			phydev_err(phydev, "invalid qca,smarteee-tw-us-1g\n");
> > @@ -341,6 +361,10 @@ static int at803x_config_init(struct phy_device *phydev)
> >  	if (ret < 0)
> >  		return ret;
> >  
> > +	ret = at803x_hibernation_mode_config(phydev);
> > +	if (ret < 0)
> > +		return ret;
> > +
> >  	return 0;
> >  }
> >  
> 
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