Re: [PATCH] rt2800: remove erroneous duplicate condition

[Stanislaw Gruszka <sgruszka@redhat.com>]

On Tue, Oct 29, 2019 at 11:05:03AM +0100, Daniel Golle wrote:
> > > --- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> > > +++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> > > @@ -5839,8 +5839,7 @@ static int rt2800_init_registers(struct rt2x00_dev *rt2x00dev)
> > >  		rt2800_register_write(rt2x00dev, TX_TXBF_CFG_0, 0x8000fc21);
> > >  		rt2800_register_write(rt2x00dev, TX_TXBF_CFG_3, 0x00009c40);
> > >  	} else if (rt2x00_rt(rt2x00dev, RT5390) ||
> > > -		   rt2x00_rt(rt2x00dev, RT5392) ||
> > > -		   rt2x00_rt(rt2x00dev, RT6352)) {
> > > +		   rt2x00_rt(rt2x00dev, RT5392)) {
> > >  		rt2800_register_write(rt2x00dev, TX_SW_CFG0, 0x00000404);
> > >  		rt2800_register_write(rt2x00dev, TX_SW_CFG1, 0x00080606);
> > >  		rt2800_register_write(rt2x00dev, TX_SW_CFG2, 0x00000000);
> > 
> > I'm not sure if initialization on different path, is proper for all
> > variants of RT6352 chipset. Particularly I noticed that configuring
> > MIMO_PS_CFG can cause problems on wt3020.
> 
> That's pretty odd, as this register is also written unconditionally
> by the vendor driver, see:
> https://github.com/wuqiong/rt2860v2-for-openwrt-mt7620/blob/master/rt2860v2/chips/rt6352.c#L529
> https://github.com/wuqiong/rt2860v2-for-openwrt-mt7620/blob/master/rt2860v2/chips/rt6352.c#L696

Today I had time to debug this a bit more. Problems on WT3020 are not
caused by MIMO_PS_CFG, but by TX_PIN_CFG setting. On this device we
should not overwrite TX_PIN_CFG. Presumably this is correct for
other devices, since code path that set TX_PIN_CFG to 0x00150F0F
was not used before due to this erroneous 'else if RT6352'.

Even if setting MMIO_PS_CFG does not cause problems, I think we
do not need to configure it and can stay with default HW value,
which is 4.

Please repost patch with TX_PIN_CFG and MIMO_PS_CFG settings removed.

> As only ChipVer >= 2 has been seen in the wild apparently, it seems

Ok, so we do not need to implement ChipVer 1 support.

> Roman implemented support for MT7620 along that codepath in the
> original driver:
> https://github.com/wuqiong/rt2860v2-for-openwrt-mt7620/blob/master/rt2860v2/chips/rt6352.c#L713
> 
> However, now looking at this more, also
> rt2800_register_write(rt2x00dev, TX_ALC_VGA3, 0x00000000);
> doesn't match that codepath in the vendor driver which sets 0x06060606.

This was changed by:

commit c2e28ef7711ffcb083474ee5f154264c6ec1ec07
Author: Tomislav Požega <pozega.tomislav@gmail.com>
Date:   Thu Dec 27 15:05:25 2018 +0100

    rt2x00: reduce tx power to nominal level on RT6352

and I think it is correct.

> Now we could really implement all the codepaths for all pkg, ver, eco
> variants of MT7620 using the accessors like I patched here:
> https://github.com/openwrt/openwrt/blob/master/target/linux/ramips/patches-4.14/300-mt7620-export-chip-version-and-pkg.patch
> (accessor for mt7620_get_eco was already in place as it is used also
> by MMC/SD driver afair)
>
> Which MT7620 chip package, version and eco is found inside the wt3020?
> (printed early on dmesg)

chipver 2 eco 6 pkg 0,

Thanks
Stanislaw