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Message-ID: <YYBBHsFEwGdPJw3b@lunn.ch>
Date: Mon, 1 Nov 2021 20:33:50 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Grygorii Strashko <grygorii.strashko@...com>
Cc: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Jakub Kicinski <kuba@...nel.org>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
Florian Fainelli <f.fainelli@...il.com>,
linux-kernel@...r.kernel.org, Vignesh Raghavendra <vigneshr@...com>
Subject: Re: [RFC PATCH] net: phy/mdio: enable mmd indirect access through
phy_mii_ioctl()
On Mon, Nov 01, 2021 at 08:28:59PM +0200, Grygorii Strashko wrote:
> This patch enables access to C22 PHY MMD address space through
I'm not sure the terminology is correct here. I think it actually
enables access to C45 address space, making use of C45 over C22.
> phy_mii_ioctl() SIOCGMIIREG/SIOCSMIIREG IOCTLs. It checks if R/W request is
> received with C45 flag enabled while MDIO bus doesn't support C45 and, in
> this case, tries to treat prtad as PHY MMD selector and use MMD API.
>
> With this change it's possible to r/w PHY MMD registers with phytool, for
> example, before:
>
> phytool read eth0/0x1f:0/0x32
> 0xffea
>
> after:
> phytool read eth0/0x1f:0/0x32
> 0x00d1
> @@ -300,8 +300,19 @@ int phy_mii_ioctl(struct phy_device *phydev, struct ifreq *ifr, int cmd)
> prtad = mii_data->phy_id;
> devad = mii_data->reg_num;
> }
> - mii_data->val_out = mdiobus_read(phydev->mdio.bus, prtad,
> - devad);
> + if (mdio_phy_id_is_c45(mii_data->phy_id) &&
> + phydev->mdio.bus->probe_capabilities <= MDIOBUS_C22) {
> + phy_lock_mdio_bus(phydev);
> +
> + mii_data->val_out = __mmd_phy_read(phydev->mdio.bus,
> + mdio_phy_id_devad(mii_data->phy_id),
> + prtad,
> + mii_data->reg_num);
> +
> + phy_unlock_mdio_bus(phydev);
> + } else {
> + mii_data->val_out = mdiobus_read(phydev->mdio.bus, prtad, devad);
> + }
The layering look wrong here. You are trying to perform MDIO bus
operation here, so it seems odd to perform __mmd_phy_read(). I wonder
if it would be cleaner to move C45 over C22 down into the mdiobus_
level API?
Andrew
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