From: Heiner Kallweit <hkallweit1@gmail.com>
To: Wong Vee Khee <vee.khee.wong@intel.com>,
Andrew Lunn <andrew@lunn.ch>,
Russell King <linux@armlinux.org.uk>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Voon Weifeng <weifeng.voon@intel.com>,
Ong Boon Leong <boon.leong.ong@intel.com>
Subject: Re: [PATCH net V2 1/1] net: phy: fix invalid phy id when probe using C22
Date: Thu, 18 Mar 2021 14:25:54 +0100 [thread overview]
Message-ID: <b63c5068-1203-fcb6-560d-1d2419bb39b0@gmail.com> (raw)
In-Reply-To: <20210318090937.26465-1-vee.khee.wong@intel.com>
On 18.03.2021 10:09, Wong Vee Khee wrote:
> When using Clause-22 to probe for PHY devices such as the Marvell
> 88E2110, PHY ID with value 0 is read from the MII PHYID registers
> which caused the PHY framework failed to attach the Marvell PHY
> driver.
>
> Fixed this by adding a check of PHY ID equals to all zeroes.
>
I was wondering whether we have, and may break, use cases where a PHY,
for whatever reason, reports PHY ID 0, but works with the genphy
driver. And indeed in swphy_read_reg() we return PHY ID 0, therefore
the patch may break the fixed phy.
Having said that I think your patch is ok, but we need a change of
the PHY ID reported by swphy_read_reg() first.
At a first glance changing the PHY ID to 0x00000001 in swphy_read_reg()
should be sufficient. This value shouldn't collide with any real world
PHY ID.
> Fixes: ee951005e95e ("net: phy: clean up get_phy_c22_id() invalid ID handling")
> Cc: stable@vger.kernel.org
> Reviewed-by: Voon Weifeng <voon.weifeng@intel.com>
> Signed-off-by: Wong Vee Khee <vee.khee.wong@intel.com>
> ---
> v2 changelog:
> - added fixes tag
> - marked for net instead of net-next
> ---
> drivers/net/phy/phy_device.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index cc38e326405a..c12c30254c11 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -809,8 +809,8 @@ static int get_phy_c22_id(struct mii_bus *bus, int addr, u32 *phy_id)
>
> *phy_id |= phy_reg;
>
> - /* If the phy_id is mostly Fs, there is no device there */
> - if ((*phy_id & 0x1fffffff) == 0x1fffffff)
> + /* If the phy_id is mostly Fs or all zeroes, there is no device there */
> + if (((*phy_id & 0x1fffffff) == 0x1fffffff) || (*phy_id == 0))
> return -ENODEV;
>
> return 0;
>
next prev parent reply other threads:[~2021-03-18 13:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 9:09 [PATCH net V2 1/1] net: phy: fix invalid phy id when probe using C22 Wong Vee Khee
2021-03-18 13:25 ` Heiner Kallweit [this message]
2021-03-18 16:02 ` Florian Fainelli
2021-03-18 16:21 ` Russell King - ARM Linux admin
2021-03-18 16:48 ` Heiner Kallweit
2021-03-18 18:14 ` Greg KH
2021-03-18 18:58 ` Florian Fainelli
2021-03-19 7:40 ` Heiner Kallweit
2021-03-19 8:56 ` Russell King - ARM Linux admin
2021-03-22 12:39 ` Wong, Vee Khee
2021-03-26 1:57 ` [net] c0da0048be: WARNING:at_net/core/devlink.c:#devlink_port_type_warn kernel test robot
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