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Date: Tue, 27 Oct 2020 01:33:14 +0000 From: Andy Duan <fugang.duan@....com> To: Greg Ungerer <gerg@...ux-m68k.org>, Andrew Lunn <andrew@...n.ch>, Dave Karr <dkarr@...x.com>, Clemens Gruber <clemens.gruber@...ruber.com> CC: Chris Heally <cphealy@...il.com>, "netdev@...r.kernel.org" <netdev@...r.kernel.org> Subject: RE: [EXT] Re: [PATCH] net: ethernet: fec: Replace interrupt driven MDIO with polled IO From: Greg Ungerer <gerg@...ux-m68k.org> Sent: Tuesday, October 27, 2020 8:18 AM > Hi Andy, > > On 22/10/20 7:04 pm, Andy Duan wrote: > > From: Greg Ungerer <gerg@...ux-m68k.org> Sent: Thursday, October 22, > > 2020 9:14 AM > >> Hi Andrew, > >> > >> On 21/10/20 11:37 pm, Andrew Lunn wrote: > >>>> + if (fep->quirks & FEC_QUIRK_CLEAR_SETUP_MII) { > >>>> + /* Clear MMFR to avoid to generate MII event by > >>>> + writing > >> MSCR. > >>>> + * MII event generation condition: > >>>> + * - writing MSCR: > >>>> + * - mmfr[31:0]_not_zero & mscr[7:0]_is_zero & > >>>> + * mscr_reg_data_in[7:0] != 0 > >>>> + * - writing MMFR: > >>>> + * - mscr[7:0]_not_zero > >>>> + */ > >>>> + writel(0, fep->hwp + FEC_MII_DATA); > >>>> + } > >>> > >>> Hi Greg > >>> > >>> The last time we discussed this, we decided that if you cannot do > >>> the quirk, you need to wait around for an MDIO interrupt, e.g. call > >>> fec_enet_mdio_wait() after setting FEC_MII_SPEED register. > >>> > >>>> > >>>> writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED); > >> > >> The code following this is: > >> > >> writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED); > >> > >> /* Clear any pending transaction complete indication */ > >> writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT); > >> > >> > >> So this is forcing a clear of the event here. Is that not good enough? > >> > >> For me on my ColdFire test target I always get a timeout if I wait > >> for a FEC_IEVENT after the FEC_MII_SPEED write. > >> > >> Regards > >> Greg > > > > Dave Karr's last patch can fix the issue, but it may introduce 30ms delay during > boot. > > Greg's patch is to add quirk flag to distinguish platform before > > clearing mmfr operation, which also can fix the issue. > > Do you mean that we can use either fix - and that is ok for all hardware types? > > Regards > Greg Yes, I think so. Thanks, Andy
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