[OpenWrt-Devel] Autoneg problems with ar8216 on kernel 3.14 (related to ticket 17800)
Felix Fietkau
nbd at openwrt.org
Sun Nov 23 19:06:29 EST 2014
On 2014-11-23 23:03, Weedy wrote:
>
> On Nov 23, 2014 4:35 PM, "Weedy" <weedy2887 at gmail.com
> <mailto:weedy2887 at gmail.com>> wrote:
>>
>>
>> On Nov 19, 2014 8:47 AM, "John Crispin" <blogic at openwrt.org
> <mailto:blogic at openwrt.org>> wrote:
>> >
>> >
>> >
>> > On 19/11/2014 14:44, Weedy wrote:
>> > >
>> > > On Oct 30, 2014 5:08 PM, "Heiner Kallweit" <hkallweit1 at gmail.com
> <mailto:hkallweit1 at gmail.com>
>> > > <mailto:hkallweit1 at gmail.com <mailto:hkallweit1 at gmail.com>>> wrote:
>> > >>
>> > >> Am 30.10.2014 um 07:22 schrieb Heiner Kallweit:
>> > >> > Am 30.10.2014 um 03:36 schrieb Florian Fainelli:
>> > >> >> Le 28/10/2014 11:46, Heiner Kallweit a écrit :
>> > >> >>> After a little more thinking about it and looking at the code I
>> > > basically have two questions:
>> > >> >>>
>> > >> >>> 1.
>> > >> >>> Is it actually needed to exclude certain phy's in
>> > > ar8xxx_phy_config_aneg?
>> > >> >>> (At least for AR8327 it doesn't get called with an addr != 0
> anyway)
>> > >> >>> Else we could remove ar8xxx_phy_config_aneg and directly register
>> > > genphy_config_aneg as
>> > >> >>> callback for autoneg configuration.
>> > >> >>
>> > >> >> Address 0 is special, since this is a MDIO broadcast address that
>> > > will usually be handled by switches as "write to all front-panel
> ports".
>> > >> >>
>> > >> >>>
>> > >> >>> 2.
>> > >> >>> Call sequence with regard to ar8216 is:
>> > >> >>> ar8216: ar8xxx_phy_probe
>> > >> >>> phy: phy_attach_direct
>> > >> >>> phy: phy_init_hw
>> > >> >>> ar8216: ar8xxx_phy_config_init
>> > >> >>> ar8216: ar8xxx_phy_config_aneg
>> > >> >>>
>> > >> >>> ar8216 driver handles AR8327/AR8337 different from the other
>> > > supported switch types.
>> > >> >>> ar8xxx_start incl. more detailed configuration is called from
>> > > ar8xxx_phy_probe already.
>> > >> >>> For the other switch types it's called from
> ar8xxx_phy_config_init.
>> > >> >>>
>> > >> >>> I wonder whether doing detailed configuration in the probe stage
>> > > might be too early.
>> > >> >>> phy_init_hw resets the switch anyway later.
>> > >> >>> Doing the detailed setup in ar8xxx_phy_config_init seems to be
>> > > more suited however
>> > >> >>> there might be good reason why it's handled the way it is.
>> > >> >>
>> > >> >> I suppose that you could re-advertise auto-negotiation by calling
>> > > genphy_config_advert() in the config_init routine.
>> > >> >
>> > >> > The actual problem is caused by BMCR_ANENABLE being cleared by the
>> > > reset in phy_init_hw.
>> > >> > As far as I can see genphy_config_advert doesn't bring back
> this flag.
>> > >> > What does genphy_config_aneg mainly do?
>> > >> > - call genphy_config_advert
>> > >> > - check if BMCR_ANENABLE is set
>> > >> > - if it's not, call genphy_restart_aneg
>> > >> > Therefore, to bring back BMCR_ANENABLE, we have to call
>> > > genphy_config_aneg or genphy_restart_aneg.
>> > >> > genphy_restart_aneg most likely is sufficient, however I don't see
>> > > that genphy_config_aneg
>> > >> > can do any harm if being called with addr == 0.
>> > >> > At least for me it works perfectly fine to call genphy_config_aneg
>> > > for all addr's.
>> > >> >
>> > >> > Rgds, Heiner
>> > >> >
>> > >> >>
>> > >> >>>
>> > >> >>> Rgds,
>> > >> >>> Heiner
>> > >> >>>
>> > >> >>>
>> > >> >>> Am 27.10.2014 um 22:00 schrieb Heiner Kallweit:
>> > >> >>>> With two different TPLINK routers (both with a AR8327N switch) I
>> > > faced the issue that with
>> > >> >>>> kernel 3.14 certain switch ports used 10MBit/half only.
>> > >> >>>> Under kernel 3.10 everything was fine and the same ports used
>> > > 1000MBit/full.
>> > >> >>>>
>> > >> >>>> As the ar8216 driver is the same I had a look at the common phy
>> > > code in drivers/net/phy.
>> > >> >>>> In function phy_init_hw in phy_device.c kernel 3.14 resets the
>> > > phy whilst 3.10 does not.
>> > >> >>>>
>> > >> >>>> The issue turned out to be that when resetting only flag
>> > > BMCR_RESET is set, not BMCR_ANENABLE.
>> > >> >>>> (In ar8216.c always both flags are set when the switch is reset)
>> > >> >>>> Therefore autoneg was not enabled. Also later in the boot
> process
>> > > it doesn't get enabled.
>> > >> >>>> Adding BMCR_ANENABLE solved the problem and now also under 3.14
>> > > all ports use 1000MBit/full.
>> > >> >>>>
>> > >> >>>> However I'm not sure whether it's a poper fix to add
>> > > BMCR_ANENABLE in this generic phy function.
>> > >> >>>> It might not be appropriate for other phy's.
>> > >> >>>>
>> > >> >>>> After resetting the switch later in the boot process
>> > > ar8xxx_phy_config_aneg is called with
>> > >> >>>> phydev->addr being 0.
>> > >> >>>> In this case the function returns immediately. Otherwise it
> would
>> > > call genphy_config_aneg.
>> > >> >>>> Calling genphy_config_aneg would also solve the problem as it
>> > > checks for BMCR_ANENABLE
>> > >> >>>> being set and sets it if needed.
>> > >> >>>> I don't know the reason why genphy_config_aneg isn't called in
>> > > case of addr 0.
>> > >> >>>> Or is this a typo and the check actually should be addr != 0 ?
>> > >> >>>>
>> > >> >>>> Rgds, Heiner
>> > >> >>>>
>> > >>
>> > >> The following rudimentary patch works fine for me with kernel
> 3.14.18 on
>> > >> TP-LINK TL-WDR4900 (mpc85xx with AR8327Nv4)
>> > >> TP-LINK TL-WDR4300 ( ar71xx with AR8327Nv2)
>> > >>
>> > >> Apart from using genphy_config_aneg also for addr==0 I replaced
>> > > msleep(1000)
>> > >> with a polling function inspired by phy_poll_reset in phy_device.c
>> > >> On AR8327 the reset actually takes less than 20ms. Sleeping for
> 1000ms
>> > >> seems to be a waste of time.
>> > >>
>> > >> Little more work would be needed to make it a proper patch:
>> > >> - move ar8xxx_phy_poll_reset more to the beginning so that it is
> defined
>> > >> before being used in any xxxx_hw_init function
>> > >> - replace msleep(1000) also in the other xxxx_hw_init functions
>> > >> - remove pr_info debug message or make it at least pr_dbg
>> > >> - insert some comments
>> > >> - use git format-patch output
>> > >>
>> > >> Rgds, Heiner
>> > >>
>> > >>
>> > >> --- ar8216.c.orig 2014-10-30 21:50:19.999723156 +0100
>> > >> +++ ar8216.c 2014-10-30 21:42:11.996481099 +0100
>> > >> @@ -1591,6 +1591,29 @@
>> > >> #endif
>> > >>
>> > >> static int
>> > >> +ar8xxx_phy_poll_reset(struct mii_bus *bus, int num_phys)
>> > >> +{
>> > >> + unsigned int sleep_msecs = 20;
>> > >> + int ret, elapsed, i;
>> > >> +
>> > >> + for(elapsed = sleep_msecs; elapsed <= 600; elapsed +=
>> > > sleep_msecs) {
>> > >> + msleep(sleep_msecs);
>> > >> + for (i = 0; i < num_phys; i++) {
>> > >> + ret = mdiobus_read(bus, i, MII_BMCR);
>> > >> + if (ret < 0) return ret;
>> > >> + if (ret & BMCR_RESET) break;
>> > >> + if (i == num_phys - 1) {
>> > >> + usleep_range(1000, 2000);
>> > >> + pr_info("ar8xxx_phy_poll_reset
>> > > finished in %u ms\n",
>> > >> + elapsed);
>> > >> + return 0;
>> > >> + }
>> > >> + }
>> > >> + }
>> > >> + return -ETIMEDOUT;
>> > >> +}
>> > >> +
>> > >> +static int
>> > >> ar8327_hw_init(struct ar8xxx_priv *priv)
>> > >> {
>> > >> struct mii_bus *bus;
>> > >> @@ -1620,7 +1643,7 @@
>> > >> mdiobus_write(bus, i, MII_BMCR, BMCR_RESET |
>> > > BMCR_ANENABLE);
>> > >> }
>> > >>
>> > >> - msleep(1000);
>> > >> + ar8xxx_phy_poll_reset(bus, AR8327_NUM_PHYS);
>> > >>
>> > >> return 0;
>> > >> }
>> > >> @@ -2840,15 +2863,6 @@
>> > >> return ret;
>> > >> }
>> > >>
>> > >> -static int
>> > >> -ar8xxx_phy_config_aneg(struct phy_device *phydev)
>> > >> -{
>> > >> - if (phydev->addr == 0)
>> > >> - return 0;
>> > >> -
>> > >> - return genphy_config_aneg(phydev);
>> > >> -}
>> > >> -
>> > >> static const u32 ar8xxx_phy_ids[] = {
>> > >> 0x004dd033,
>> > >> 0x004dd034, /* AR8327 */
>> > >> @@ -3020,7 +3034,7 @@
>> > >> .remove = ar8xxx_phy_remove,
>> > >> .detach = ar8xxx_phy_detach,
>> > >> .config_init = ar8xxx_phy_config_init,
>> > >> - .config_aneg = ar8xxx_phy_config_aneg,
>> > >> + .config_aneg = genphy_config_aneg,
>> > >> .read_status = ar8xxx_phy_read_status,
>> > >> .driver = { .owner = THIS_MODULE },
>> > >> };
>> > >> _______________________________________________
>> > >> openwrt-devel mailing list
>> > >> openwrt-devel at lists.openwrt.org
> <mailto:openwrt-devel at lists.openwrt.org>
> <mailto:openwrt-devel at lists.openwrt.org
> <mailto:openwrt-devel at lists.openwrt.org>>
>> > >> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>> > >
>> > > I feel like this shouldn't die off in the depths of the ML
>> > >
>> >
>> > we had a call about it today, this patch and the other ar821x patches
>> > will be handled soon
>>
>> You guys bumped trunk to 3.14 but didn't fix this.
>
> It's also broken in 43342.
>
> For me this manifests as the WAN port is stuck at 1000T so my 100T DSL
> modem doesn't exist. Lucky I keep spare switches around.
On what device is it broken for you? I did apply Heiner Kallweit's
fixes, and it worked for me.
- Felix
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