netdev - Re: [PATCH v2] net: lan78xx: prevent LAN88XX specific operations

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Message-ID: <1650367438.466155.1671540467993.JavaMail.zimbra@savoirfairelinux.com>
Date:   Tue, 20 Dec 2022 07:47:47 -0500 (EST)
From:   Enguerrand de Ribaucourt 
        <enguerrand.de-ribaucourt@...oirfairelinux.com>
To:     Paolo Abeni <pabeni@...hat.com>
Cc:     netdev <netdev@...r.kernel.org>,
        woojung huh <woojung.huh@...rochip.com>,
        davem <davem@...emloft.net>,
        UNGLinuxDriver <UNGLinuxDriver@...rochip.com>
Subject: Re: [PATCH v2] net: lan78xx: prevent LAN88XX specific operations

----- Original Message -----
> From: "Paolo Abeni" <pabeni@...hat.com>
> To: "Enguerrand de Ribaucourt" <enguerrand.de-ribaucourt@...oirfairelinux.com>, "netdev" <netdev@...r.kernel.org>
> Cc: "woojung huh" <woojung.huh@...rochip.com>, "davem" <davem@...emloft.net>, "UNGLinuxDriver"
> <UNGLinuxDriver@...rochip.com>
> Sent: Tuesday, December 20, 2022 1:41:08 PM
> Subject: Re: [PATCH v2] net: lan78xx: prevent LAN88XX specific operations

> On Tue, 2022-12-20 at 12:37 +0100, Enguerrand de Ribaucourt wrote:
> > Some operations during the cable switch workaround modify the register
> > LAN88XX_INT_MASK of the PHY. However, this register is specific to the
> > LAN8835 PHY. For instance, if a DP8322I PHY is connected to the LAN7801,
> > that register (0x19), corresponds to the LED and MAC address
> > configuration, resulting in unapropriate behavior.

> > Use the generic phy interrupt functions instead.

> > Fixes: 89b36fb5e532 ("lan78xx: Lan7801 Support for Fixed PHY")
> > Reviewed-by: Paolo Abeni <pabeni@...hat.com>;

> You should not attach this tag (or acked-by) on your own.

Thanks, I'm still new with the patching process.

> The following is not even the code I was _asking_ about...

>> Signed-off-by: Enguerrand de Ribaucourt
> > <enguerrand.de-ribaucourt@...oirfairelinux.com>
> > ---
> > drivers/net/usb/lan78xx.c | 14 +++-----------
> > 1 file changed, 3 insertions(+), 11 deletions(-)

> > diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
> > index f18ab8e220db..65d5d54994ff 100644
> > --- a/drivers/net/usb/lan78xx.c
> > +++ b/drivers/net/usb/lan78xx.c
> > @@ -28,6 +28,7 @@
> > #include <linux/phy_fixed.h>
> > #include <linux/of_mdio.h>
> > #include <linux/of_net.h>
> > +#include <linux/phy.h>
> > #include "lan78xx.h"

> > #define DRIVER_AUTHOR "WOOJUNG HUH <woojung.huh@...rochip.com>"
>> @@ -2123,10 +2124,7 @@ static void lan78xx_link_status_change(struct net_device
> > *net)
> > * at forced 100 F/H mode.
> > */
> > if (!phydev->autoneg && (phydev->speed == 100)) {
> > - /* disable phy interrupt */
> > - temp = phy_read(phydev, LAN88XX_INT_MASK);
> > - temp &= ~LAN88XX_INT_MASK_MDINTPIN_EN_;
> > - phy_write(phydev, LAN88XX_INT_MASK, temp);
> > + phy_disable_interrupts(phydev);

> > temp = phy_read(phydev, MII_BMCR);
> > temp &= ~(BMCR_SPEED100 | BMCR_SPEED1000);
>> @@ -2134,13 +2132,7 @@ static void lan78xx_link_status_change(struct net_device
> > *net)
> > temp |= BMCR_SPEED100;
> > phy_write(phydev, MII_BMCR, temp); /* set to 100 later */

> > - /* clear pending interrupt generated while workaround */
> > - temp = phy_read(phydev, LAN88XX_INT_STS);
> > -
> > - /* enable phy interrupt back */
> > - temp = phy_read(phydev, LAN88XX_INT_MASK);
> > - temp |= LAN88XX_INT_MASK_MDINTPIN_EN_;
> > - phy_write(phydev, LAN88XX_INT_MASK, temp);
> > + phy_request_interrupt(phydev);

> This looks wrong. Should probably be:

> phy_enable_interrupts(phydev);

phy_enable_interrupts isn't exported in the header. I'll add a
dedicated commit for that.

> Paolo