[U-Boot] dm: pinctrl: Prevent (re-)configuring pins when already done before relocation

Lukasz Majewski
2019-01-08T23:24:42Z

Hi Alex,

> On Tue, Jan 8, 2019 at 10:52 PM Lukasz Majewski <lukma@denx.de> wrote:
> >
> > Hi Alex,
> >
> > > On Thu, Dec 27, 2018 at 3:49 PM Tom Rini <trini@konsulko.com>
> > > wrote:
> > > >
> > > > On Tue, Dec 18, 2018 at 12:30:50PM +0100, Lukasz Majewski wrote:
> > > >
> > > > > This commit prevents from re-configuring pins if those were
> > > > > configured before relocation.
> > > > >
> > > > > Some pins - like UART or DDR must be setup before relocation
> > > > > (as they have 'u-boot,dm-pre-reloc' property set in DTS).
> > > > > Without this change, those pins are re-configured after
> > > > > relocation (pre_reloc_only = 0, so we do not "continue").
> > > > > Such behavior may be a problem for DDR PAD configuration, as
> > > > > they might be already leveled/tuned with original setup).
> > > > >
> > > > > Signed-off-by: Lukasz Majewski <lukma@denx.de>
> > > >
> > > > Applied to u-boot/master, thanks!
> > > >
> > >
> > > I've bisected out to this commit and it's slightly broken things
> > > for me on an AM3352. It all works fine so long as I boot MLO from
> > > MMC (so the MMC is probed, pinctrl setup), but if I boot from
> > > UART then I get to full U-Boot, MMC hasn't been probed and the
> > > pinmuxing isn't set up for the MMC.
> >
> > I suppose that the pinmux node have set "u-boot,dm-pre-reloc"
> > property?
> >
>
> Yeah, well "u-boot,dm-spl", though now I re-read the docs I guess
> that's equivalent to "u-boot,dm-pre-reloc" as I've no TPL.

I do need to check this -> as in my case I do have
"u-boot,dm-pre-reloc" property. And yes, in my case I do not have TPL
too (just SPL).

>
> > The problem is not with lack of eMMC probing - it is with pinctrl
> > nodes having "u-boot,dm-pre-reloc" set in DTS and the eMMC is
> > probed after MLO/SPL.
> > It looks like your use case implicitly depends on pinmux being
> > reconfigured no matter if we are pre-relocated (MLO) or afterwards.
> >
>
> Yes, that's a much clearer description...

Frankly, your mail opened my eyes to a use case which was handled (I
assume on purpose) with the old code - the "cross" boot with pinmux
and devices.

For example boot from UART (MLO/SPL) and then continue with eMMC (which
require pinmux).

>

Best regards,

Lukasz Majewski

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