net: mtk_sgmii: implement mtk_pcs_ops

  From: Alexander Couzens <lynxis@fe80.eu>

Implement mtk_pcs_ops for the SGMII pcs to read the current state
of the hardware.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>

Fixes: 14a44ab0330d ("net: mtk_eth_soc: partially convert to phylink_pcs")
---
without this Patch i get this trace in 6.1-rc1 when enabling the left
sfp (eth1) on bpi-r3 (crash happens in phylink core because a NULL-pointer,
so fixes-Tag is a guess):

[  108.302810] Unable to handle kernel execute from non-executable memory at virtual address 0000000000000000
[  108.312462] Mem abort info:
[  108.315263]   ESR = 0x0000000086000005
[  108.319003]   EC = 0x21: IABT (current EL), IL = 32 bits
[  108.324335]   SET = 0, FnV = 0
[  108.327378]   EA = 0, S1PTW = 0
[  108.330505]   FSC = 0x05: level 1 translation fault
[  108.335375] user pgtable: 4k pages, 39-bit VAs, pgdp=00000000419be000
[  108.341798] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000, pu
d=0000000000000000
[  108.350489] Internal error: Oops: 0000000086000005 [#1] SMP
[  108.356047] Modules linked in: cdc_mbim cdc_ncm cdc_wdm cdc_ether qcserial us
a_wwan usbnet usbser
a Mmeisis
ge from syslogd@bpi-r3 at Aug  7 15:26:54 ...
 kernel:[  108.350489] Internal error: Oops: 0000000086000005 [#1] SMP
[  108.376743] CPU: 3 PID: 8 Comm: kworker/u8:0 Not tainted 6.0.0-bpi-r3 #1
[  108.383461] Hardware name: Bananapi BPI-R3 (sdmmc) (DT)
[  108.388671] Workqueue: events_power_efficient phylink_resolve
[  108.394411] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  108.401355] pc : 0x0
[  108.403531] lr : phylink_mac_pcs_get_state+0x7c/0x100
[  108.408572] sp : ffffffc00963bd00
[  108.411873] x29: ffffffc00963bd00 x28: 0000000000000000 x27: 0000000000000000
[  108.418994] x26: ffffff80000ed074 x25: ffffff800001c105 x24: 0000000000000000
[  108.426116] x23: ffffff80022f8cd8 x22: ffffff80022f8d30 x21: ffffff80022f8c00
[  108.433236] x20: 0000000000000000 x19: ffffff8000126040 x18: 0000000000000000
[  108.440357] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[  108.447478] x14: ffffffffffffffff x13: 0000000000000030 x12: 0101010101010101
[  108.454598] x11: 7f7f7f7f7f7f7f7f x10: fefefefefefefeff x9 : ffffff80000ed07c
[  108.461720] x8 : fefefefefefefeff x7 : 0000000000000017 x6 : ffffff80000ed074
[  108.468840] x5 : 0000000000000000 x4 : 0000020000006440 x3 : 00000000fffffffa
[  108.475960] x2 : 0000000000000000 x1 : ffffffc00963bd80 x0 : ffffff80014c3ab0
[  108.483082] Call trace:
[  108.485516]  0x0
[  108.487344]  phylink_resolve+0x248/0x520
[  108.491256]  process_one_work+0x204/0x478
[  108.495256]  worker_thread+0x148/0x4c0
[  108.498993]  kthread+0xdc/0xe8
[  108.502037]  ret_from_fork+0x10/0x20
[  108.505608] Code: bad PC value
[  108.508652] ---[ end trace 0000000000000000 ]---
[  108.513255] Kernel panic - not syncing: Oops: Fatal exception
[  108.518984] SMP: stopping secondary CPUs
[  108.522894] Kernel Offset: disabled
[  108.526369] CPU features: 0x00000,00800084,0000420b
[  108.531232] Memory Limit: none
[  108.534274] Rebooting in 1 seconds..
---
 drivers/net/ethernet/mediatek/mtk_sgmii.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
  

Hi,

A couple of points:

On Tue, Oct 18, 2022 at 05:35:06PM +0200, Frank Wunderlich wrote:
> diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
> index 736839c84130..9614973fd9c4 100644
> --- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
> +++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
> @@ -122,10 +122,25 @@ static void mtk_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
>  	regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
>  }
>  
> +static void mtk_pcs_get_state(struct phylink_pcs *pcs, struct phylink_link_state *state)
> +{
> +	struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
> +	unsigned int val;
> +
> +	regmap_read(mpcs->regmap, mpcs->ana_rgc3, &val);
> +	state->speed = val & RG_PHY_SPEED_3_125G ? SPEED_2500 : SPEED_1000;
> +
> +	regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
> +	state->an_complete = !!(val & SGMII_AN_COMPLETE);
> +	state->link = !!(val & SGMII_LINK_STATYS);
> +	state->pause = 0;

Finally, something approaching a reasonable implementation for this!
Two points however:
1) There's no need to set state->pause if there is no way to get that
   state.
2) There should also be a setting for state->pause.

> +}
> +
>  static const struct phylink_pcs_ops mtk_pcs_ops = {
>  	.pcs_config = mtk_pcs_config,
>  	.pcs_an_restart = mtk_pcs_restart_an,
>  	.pcs_link_up = mtk_pcs_link_up,
> +	.pcs_get_state = mtk_pcs_get_state,

Please keep this in order - pcs_get_state should be just before
pcs_config.

Thanks.
  

Am 18. Oktober 2022 18:39:01 MESZ schrieb "Russell King (Oracle)" <linux@armlinux.org.uk>:
>Hi,
>
>A couple of points:
>
>On Tue, Oct 18, 2022 at 05:35:06PM +0200, Frank Wunderlich wrote:

>> +	regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
>> +	state->an_complete = !!(val & SGMII_AN_COMPLETE);
>> +	state->link = !!(val & SGMII_LINK_STATYS);
>> +	state->pause = 0;
>
>Finally, something approaching a reasonable implementation for this!
>Two points however:
>1) There's no need to set state->pause if there is no way to get that
>   state.
>2) There should also be a setting for state->pause.

Currently it looks like pause cannot be controlled in sgmii-mode so we disabled it here to not leave it undefined. Should i drop assignment here?

>> +}
>> +
>>  static const struct phylink_pcs_ops mtk_pcs_ops = {
>>  	.pcs_config = mtk_pcs_config,
>>  	.pcs_an_restart = mtk_pcs_restart_an,
>>  	.pcs_link_up = mtk_pcs_link_up,
>> +	.pcs_get_state = mtk_pcs_get_state,
>
>Please keep this in order - pcs_get_state should be just before
>pcs_config.

Ok,will change order

regards Frank
  

On Thu, Oct 20, 2022 at 07:54:49AM +0200, Frank Wunderlich wrote:
> Am 18. Oktober 2022 18:39:01 MESZ schrieb "Russell King (Oracle)" <linux@armlinux.org.uk>:
> >Hi,
> >
> >A couple of points:
> >
> >On Tue, Oct 18, 2022 at 05:35:06PM +0200, Frank Wunderlich wrote:
> 
> >> +	regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
> >> +	state->an_complete = !!(val & SGMII_AN_COMPLETE);
> >> +	state->link = !!(val & SGMII_LINK_STATYS);
> >> +	state->pause = 0;
> >
> >Finally, something approaching a reasonable implementation for this!
> >Two points however:
> >1) There's no need to set state->pause if there is no way to get that
> >   state.
> >2) There should also be a setting for state->pause.
> 
> Currently it looks like pause cannot be controlled in sgmii-mode so we disabled it here to not leave it undefined. Should i drop assignment here?

Why do you think it would be undefined?

static void phylink_mac_pcs_get_state(struct phylink *pl,
                                      struct phylink_link_state *state)
{
...
        if  (state->an_enabled) {
...
                state->pause = MLO_PAUSE_NONE;
        } else {
,,,
                state->pause = pl->link_config.pause;
	}
...
        if (pl->pcs)
                pl->pcs->ops->pcs_get_state(pl->pcs, state);

So, phylink will call your pcs_get_state() function having initialised
it to something sensible.
  

> Gesendet: Donnerstag, 20. Oktober 2022 um 10:33 Uhr
> Von: "Russell King (Oracle)" <linux@armlinux.org.uk>
> An: "Frank Wunderlich" <frank-w@public-files.de>
> Cc: "Frank Wunderlich" <linux@fw-web.de>, linux-mediatek@lists.infradead.org, "Alexander Couzens" <lynxis@fe80.eu>, "Felix Fietkau" <nbd@nbd.name>, "John Crispin" <john@phrozen.org>, "Sean Wang" <sean.wang@mediatek.com>, "Mark Lee" <Mark-MC.Lee@mediatek.com>, "David S. Miller" <davem@davemloft.net>, "Eric Dumazet" <edumazet@google.com>, "Jakub Kicinski" <kuba@kernel.org>, "Paolo Abeni" <pabeni@redhat.com>, "Matthias Brugger" <matthias.bgg@gmail.com>, netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
> Betreff: Re: [PATCH] net: mtk_sgmii: implement mtk_pcs_ops
>
> On Thu, Oct 20, 2022 at 07:54:49AM +0200, Frank Wunderlich wrote:
> > Am 18. Oktober 2022 18:39:01 MESZ schrieb "Russell King (Oracle)" <linux@armlinux.org.uk>:
> > >Hi,
> > >
> > >A couple of points:
> > >
> > >On Tue, Oct 18, 2022 at 05:35:06PM +0200, Frank Wunderlich wrote:
> >
> > >> +	regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
> > >> +	state->an_complete = !!(val & SGMII_AN_COMPLETE);
> > >> +	state->link = !!(val & SGMII_LINK_STATYS);
> > >> +	state->pause = 0;
> > >
> > >Finally, something approaching a reasonable implementation for this!
> > >Two points however:
> > >1) There's no need to set state->pause if there is no way to get that
> > >   state.
> > >2) There should also be a setting for state->pause.
> >
> > Currently it looks like pause cannot be controlled in sgmii-mode so we disabled it here to not leave it undefined. Should i drop assignment here?
>
> Why do you think it would be undefined?
>
> static void phylink_mac_pcs_get_state(struct phylink *pl,
>                                       struct phylink_link_state *state)
> {
> ...
>         if  (state->an_enabled) {
> ...
>                 state->pause = MLO_PAUSE_NONE;
>         } else {
> ,,,
>                 state->pause = pl->link_config.pause;
> 	}
> ...
>         if (pl->pcs)
>                 pl->pcs->ops->pcs_get_state(pl->pcs, state);
>
> So, phylink will call your pcs_get_state() function having initialised
> it to something sensible.

ok, then i drop the pause setting for now

regards Frank