netdev - Re: [PATCH V2 3/3] net: bgmac: use PHY subsystem for initializing PHY

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Message-ID: <08f74e19-f9b2-a0ea-ee21-d35cbdf6ee76@gmail.com>
Date:   Sat, 28 Jan 2017 19:08:31 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Rafał Miłecki <zajec5@...il.com>,
        "David S . Miller" <davem@...emloft.net>
Cc:     Jon Mason <jon.mason@...adcom.com>,
        Felix Fietkau <nbd@...nwrt.org>, netdev@...r.kernel.org,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: Re: [PATCH V2 3/3] net: bgmac: use PHY subsystem for initializing PHY



On 01/28/2017 01:08 PM, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@...ecki.pl>
> 
> This adds support for using bgmac with PHYs supported by standalone PHY
> drivers. Having any PHY initialization in bgmac is hacky and shouldn't
> be extended but rather removed if anyone has hardware to test it.
> 
> Signed-off-by: Rafał Miłecki <rafal@...ecki.pl>
> ---
>  drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c b/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
> index 9d9984999dce..6ce80cbcb48e 100644
> --- a/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
> +++ b/drivers/net/ethernet/broadcom/bgmac-bcma-mdio.c
> @@ -132,6 +132,10 @@ static void bcma_mdio_phy_init(struct bgmac *bgmac)
>  	struct bcma_chipinfo *ci = &bgmac->bcma.core->bus->chipinfo;
>  	u8 i;
>  
> +	/* For some legacy hardware we do chipset-based PHY initialization here
> +	 * without even detecting PHY ID. It's hacky and should be cleaned as
> +	 * soon as someone can test it.
> +	 */
>  	if (ci->id == BCMA_CHIP_ID_BCM5356) {
>  		for (i = 0; i < 5; i++) {
>  			bcma_mdio_phy_write(bgmac, i, 0x1f, 0x008b);
> @@ -140,6 +144,7 @@ static void bcma_mdio_phy_init(struct bgmac *bgmac)
>  			bcma_mdio_phy_write(bgmac, i, 0x12, 0x2aaa);
>  			bcma_mdio_phy_write(bgmac, i, 0x1f, 0x000b);
>  		}
> +		return;

That part is clearly initializing the built-in Ethernet switch's PHYs,
and so the natural place for that would be to stick these init values
into the Broadcom PHY driver. When b53-srab/b53_common attaches the
switch, it will scan all of these port's builtin PHYs and bind to an
appropriate PHY driver which could have this initialization as part of
the config_init routine for instance. Right now, we are most likely
using the Generic PHY.

Here are the different PHY IDs you should read from these models if you
want to make a subsequent patch that moves this initialization down to
the Broadcom PHY driver:

5356: 0x03625DA0
5357/53572: 0x03625F00
4749: could either be 0x600D85F0 or the same as 53010 (0x600D8760),
unclear where that product came from... Jon, would you know by chance?
-- 
Florian