netdev - RE: [PATCH net-next 2/2] net: stmmac: Add callbacks for DWC xpcs Energy Efficient Ethernet

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CO1PR11MB50447EDBEB4835C3EB5B3C7A9D2D9@CO1PR11MB5044.namprd11.prod.outlook.com>
Date:   Mon, 17 May 2021 11:37:12 +0000
From:   "Sit, Michael Wei Hong" <michael.wei.hong.sit@...el.com>
To:     Russell King <linux@...linux.org.uk>
CC:     "Jose.Abreu@...opsys.com" <Jose.Abreu@...opsys.com>,
        "andrew@...n.ch" <andrew@...n.ch>,
        "hkallweit1@...il.com" <hkallweit1@...il.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "peppe.cavallaro@...com" <peppe.cavallaro@...com>,
        "alexandre.torgue@...s.st.com" <alexandre.torgue@...s.st.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "mcoquelin.stm32@...il.com" <mcoquelin.stm32@...il.com>,
        "Voon, Weifeng" <weifeng.voon@...el.com>,
        "Ong, Boon Leong" <boon.leong.ong@...el.com>,
        "Tan, Tee Min" <tee.min.tan@...el.com>,
        "vee.khee.wong@...ux.intel.com" <vee.khee.wong@...ux.intel.com>,
        "Wong, Vee Khee" <vee.khee.wong@...el.com>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH net-next 2/2] net: stmmac: Add callbacks for DWC xpcs
 Energy Efficient Ethernet



> -----Original Message-----
> From: Russell King <linux@...linux.org.uk>
> Sent: Monday, 17 May, 2021 6:54 PM
> To: Sit, Michael Wei Hong <michael.wei.hong.sit@...el.com>
> Cc: Jose.Abreu@...opsys.com; andrew@...n.ch;
> hkallweit1@...il.com; kuba@...nel.org;
> netdev@...r.kernel.org; peppe.cavallaro@...com;
> alexandre.torgue@...s.st.com; davem@...emloft.net;
> mcoquelin.stm32@...il.com; Voon, Weifeng
> <weifeng.voon@...el.com>; Ong, Boon Leong
> <boon.leong.ong@...el.com>; Tan, Tee Min
> <tee.min.tan@...el.com>; vee.khee.wong@...ux.intel.com;
> Wong, Vee Khee <vee.khee.wong@...el.com>; linux-stm32@st-
> md-mailman.stormreply.com; linux-arm-
> kernel@...ts.infradead.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH net-next 2/2] net: stmmac: Add callbacks for
> DWC xpcs Energy Efficient Ethernet
> 
> On Mon, May 17, 2021 at 05:43:32PM +0800, Michael Sit Wei Hong
> wrote:
> > Link xpcs callback functions for MAC to configure the xpcs EEE
> feature.
> >
> > The clk_eee frequency is used to calculate the
> MULT_FACT_100NS. This
> > is to adjust the clock tic closer to 100ns.
> >
> > Signed-off-by: Michael Sit Wei Hong
> <michael.wei.hong.sit@...el.com>
> 
> What is the initial state of the EEE configuration before the first
> call to stmmac_ethtool_op_set_eee()? Does it reflect the default
> EEE settings?

The register values before the first call are the default reset values in
the registers. The reset values assumes the clk_eee_i time period is 10ns,
Hence, the reset value is set to 9.
According to the register description,
This value should be programmed such that the
clk_eee_i_time_period * (MULT_FACT_100NS + 1) should be
within 80 ns to 120 ns.

Since we are using a fixed 19.2MHz clk_eee, which is 52ns,
we are setting the value to 1.
> 
> --
> RMK's Patch system:
> https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at
> last!