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Subject: Re: [PATCH v2] net: bcmgenet: Fix attaching to PYH failed on RPi 4B
To:     Jian-Hong Pan <jhp@endlessos.org>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        Doug Berger <opendmb@gmail.com>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        bcm-kernel-feedback-list@broadcom.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux@endlessos.org,
        linux-rpi-kernel@lists.infradead.org
References: <CAPpJ_ecJxUjvxEb+3GLmtQyxhAZ3Tqk+hoUbSowG1bi+739u-g@mail.gmail.com>
 <20210623032802.3377-1-jhp@endlessos.org>
From:   Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <aa2ec0dd-6b43-099f-da0a-768d1668ec50@gmail.com>
Date:   Tue, 22 Jun 2021 21:00:55 -0700
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The subject should be fixed s/PYH/PHY/ and also probably reworded to be:

net: bcmgenet: Add mdio-bcm-unimac soft dependency

On 6/22/2021 8:28 PM, Jian-Hong Pan wrote:
> The Broadcom UniMAC MDIO bus from mdio-bcm-unimac module comes too late.

It is not just coming too late, there is also no way for the module 
loader to figure out the dependency between GENET and its MDIO bus 
driver unless we provide this MODULE_SOFTDEP hint.

> So, GENET cannot find the ethernet PHY on UniMAC MDIO bus. This leads
> GENET fail to attach the PHY as following log:
> 
> bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000
> ...
> could not attach to PHY
> bcmgenet fd580000.ethernet eth0: failed to connect to PHY
> uart-pl011 fe201000.serial: no DMA platform data
> libphy: bcmgenet MII bus: probed
> ...
> unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus
> 
> This patch adds the soft dependency to load mdio-bcm-unimac module
> before genet module to avoid the issue.
> 
> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=213485
> Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Fixes: 9a4e79697009 ("net: bcmgenet: utilize generic Broadcom UniMAC 
MDIO controller driver")

> ---
> v2: Load mdio-bcm-unimac before genet module instead of trying to
>      connect the PHY in a loop.
> 
>   drivers/net/ethernet/broadcom/genet/bcmgenet.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> index fcca023f22e5..41f7f078cd27 100644
> --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> @@ -4296,3 +4296,4 @@ MODULE_AUTHOR("Broadcom Corporation");
>   MODULE_DESCRIPTION("Broadcom GENET Ethernet controller driver");
>   MODULE_ALIAS("platform:bcmgenet");
>   MODULE_LICENSE("GPL");
> +MODULE_SOFTDEP("pre: mdio-bcm-unimac");
> 

-- 
Florian