From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1A9B12E57 for ; Fri, 10 Nov 2023 09:33:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="psGwELNb" Received: from relay6-d.mail.gandi.net (relay6-d.mail.gandi.net [217.70.183.198]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B88A244A4; Fri, 10 Nov 2023 01:33:31 -0800 (PST) Received: by mail.gandi.net (Postfix) with ESMTPSA id DF6CCC0010; Fri, 10 Nov 2023 09:33:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1699608810; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nC0pAlOXIGUdD+VbkSZGUyt+AICBgKUhgiU0tdd5070=; b=psGwELNbfHZ+a8j1bBxaVMw71b/wkWrnwxPY/Do7fG5XWdEyK0WagG8cyoVvrbsDHAI9xr 0sCuonz2sXS20x2HDGI1tSEwSY7oFYfB5yIcPkhhBvLaaqUYX2iTLjwv4sAnrYlabel93t /88QQyQqhw4MaF1wePocA4xTb8cDK+VH9ur5H/rjsh5gLWFBP4J0QfBkLfutGCICt/LvAt X/vls4T4QRB9tOkeK5sxtn/LFIePkbwDye6Kbo0hUtNdVKR6Uw/ixu0xFNacAHB8vdoA8v J6+4gg4v2GmXtPgwJxRcFa2xvBnVHLXGx1aYfVdb8hXu3O7uV1noXURToMpdRQ== Date: Fri, 10 Nov 2023 10:33:28 +0100 From: Maxime Chevallier To: Jie Luo Cc: , , , , , , , , Subject: Re: [PATCH v2 1/3] net: phy: at803x: add QCA8084 ethernet phy support Message-ID: <20231110103328.0bc3d28f@fedora> In-Reply-To: <46d61a29-96bf-868b-22b9-a31e48576803@quicinc.com> References: <20231108113445.24825-1-quic_luoj@quicinc.com> <20231108113445.24825-2-quic_luoj@quicinc.com> <20231108131250.66d1c236@fedora> <423a3ee3-bed5-02f9-f872-7b5dba64f994@quicinc.com> <20231109101618.009efb45@fedora> <0898312d-4796-c142-6401-c9d802d19ff4@quicinc.com> <46d61a29-96bf-868b-22b9-a31e48576803@quicinc.com> Organization: Bootlin X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: maxime.chevallier@bootlin.com On Fri, 10 Nov 2023 17:17:58 +0800 Jie Luo wrote: > On 11/10/2023 4:53 PM, Jie Luo wrote: > >=20 > >=20 > > On 11/9/2023 5:16 PM, Maxime Chevallier wrote: =20 > >> Hello, > >> > >> On Thu, 9 Nov 2023 16:32:36 +0800 > >> Jie Luo wrote: > >> > >> [...] > >> =20 > >>>> What I understand from this is that this PHY can be used either as a > >>>> switch, in which case port 4 would be connected to the host interface > >>>> at up to 2.5G, or as a quad-phy, but since it uses QUSGMII the link > >>>> speed would be limited to 1G per-port, is that correct ? =20 > >>> > >>> When the PHY works on the interface mode QUSGMII for quad-phy, all 4 > >>> PHYs can support to the max link speed 2.5G, actually the PHY can > >>> support to max link speed 2.5G for all supported interface modes > >>> including qusgmii and sgmii. =20 > >> > >> I'm a bit confused then, as the USGMII spec says that Quad USGMII real= ly > >> is for quad 10/100/1000 speeds, using 10b/8b encoding. > >> > >> Aren't you using the USXGMII mode instead, which can convey 4 x 2.5Gbps > >> =C2=A0 with 66b/64b encoding ? > >> > >> Thanks, > >> > >> Maxime =20 > >=20 > > Hi Maxime, > > Yes, for quad PHY mode, it is using 66b/64 encoding. > >=20 > > it seems that PHY_INTERFACE_MODE_USXGMII is for single port, > > so i take the interface name PHY_INTERFACE_MODE_QUSGMII for > > quad PHYs here. > >=20 > > can we apply PHY_INTERFACE_MODE_USXGMII to quad PHYs in this > > case(qca8084 quad PHY mode)? > >=20 > > Thanks, > > Jie. =20 >=20 > one more thing, if we use the PHY_INTERFACE_MODE_USXGMII for > the quad PHY here, the MAC serdes can't distinguish the actual > mode PHY_INTERFACE_MODE_USXGMII and 10G-QXGMII(qca8084 quad phy mode), > the MAC serdes has the different configurations for usxgmii(10g single=20 > port) and qxsgmii(quad PHY). Yes you do need a way to know which mode to use, what I'm wondering is that the usxgmii spec actually defines something like 9 different modes ( 1/2/4/8 ports, with a total bandwidth ranging from 2.5Gbps to 20 Gbps ), should we define a phy mode for all of these variants, or should we have another way of getting the mode variant (like, saying I want to use usxgmii, in 4 ports mode, with the serdes at 10.3125Gbps). That being said, QUSGMII already exists to define a specific variant of USGMII, so maybe adding 10G-QXGMII is fine... Also, net-next is still currently closed.