DM_SERIAL is broken for Kirkwood boards

[Tom Rini]

On Fri, Jan 27, 2023 at 01:31:06PM +0100, Stefan Roese wrote:
> Hi Tony,
> 
> On 1/27/23 07:13, Tony Dinh wrote:
> > Hi all,
> > 
> > On Thu, Jan 26, 2023 at 3:38 PM Tony Dinh <mibodhi at gmail.com> wrote:
> > > 
> > > Hi all,
> > > 
> > > I ran some tests today (Pogo V4 and NSA310S boards) with the latest
> > > master branch and saw the same behavior we've seen before. The boards
> > > hung, and the serial console was silent after kwboot finished
> > > transferring the u-boot image. I'm running with this DTSI patch below
> > > (to enable dm-pre-reloc for uart0).
> > > 
> > > If I deselected DM_SERIAL then both boards booted OK with kwboot.
> > > 
> > > diff --git a/arch/arm/dts/kirkwood-nsa310s.dts
> > > b/arch/arm/dts/kirkwood-nsa310s.dts
> > > index 09ee76c2a2..6c5a991fde 100644
> > > --- a/arch/arm/dts/kirkwood-nsa310s.dts
> > > +++ b/arch/arm/dts/kirkwood-nsa310s.dts
> > > @@ -317,3 +317,8 @@
> > >   &pcie0 {
> > >          status = "okay";
> > >   };
> > > +
> > > +&uart0 {
> > > +        u-boot,dm-pre-reloc;
> > > +        status = "okay";
> > > +};
> > > diff --git a/arch/arm/dts/kirkwood-pogoplug-series-4.dts
> > > b/arch/arm/dts/kirkwood-pogoplug-series-4.dts
> > > index 5aa4669ae2..ef495d69f5 100644
> > > --- a/arch/arm/dts/kirkwood-pogoplug-series-4.dts
> > > +++ b/arch/arm/dts/kirkwood-pogoplug-series-4.dts
> > > @@ -98,6 +98,7 @@
> > >   };
> > > 
> > >   &uart0 {
> > > +       u-boot,dm-pre-reloc;
> > >          status = "okay";
> > >   };
> > > 
> > > @Michael, it would be great if you could try with your Buffalo board,
> > > and see if you will experience the same behavior.
> > 
> > Looks like this commit was the indirect cause of the problem.
> > 
> > Convert CONFIG_SYS_NS16550_MEM32 et al to Kconfig
> > https://github.com/u-boot/u-boot/commit/9591b63531fa5a34698ee7bb3800af6c4ea6ba2f
> > 
> > -CONFIG_SYS_NS16550=y
> > +CONFIG_SYS_NS16550_SERIAL=y
> > +CONFIG_SYS_NS16550_REG_SIZE=-4
> 
> Thanks for digging into this. Could you perhaps prepare a patch like
> this:
> 
> diff --git a/arch/arm/mach-kirkwood/Kconfig b/arch/arm/mach-kirkwood/Kconfig
> index 45cc9326368c..438f86922310 100644
> --- a/arch/arm/mach-kirkwood/Kconfig
> +++ b/arch/arm/mach-kirkwood/Kconfig
> @@ -15,6 +15,7 @@ config SHEEVA_88SV131
>  config KIRKWOOD_COMMON
>         bool
>         select DM_SERIAL
> +       select SYS_NS16550_SERIAL
> 
>  config HAS_CUSTOM_SYS_INIT_SP_ADDR
>          bool "Use a custom location for the initial stack pointer address"
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index bb5083201b38..7b575295746b 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -773,7 +773,7 @@ config SYS_NS16550_REG_SIZE
>         int "ns16550 register width and endianness"
>         depends on SYS_NS16550_SERIAL || SPL_SYS_NS16550_SERIAL
>         range -4 4
> -       default -4 if ARCH_OMAP2PLUS || ARCH_SUNXI
> +       default -4 if ARCH_OMAP2PLUS || ARCH_SUNXI || ARCH_KIRKWOOD
>         default 1
>         help
>           Indicates register width and also endianness. If positive,
> big-endian
> 
> Does this work for you?

Wait, when do you need serial and what are you select'ing for, exactly?
The ns16550 driver stuff is indeed a bit of a mess, option wise, but
SYS_NS16550 and SYS_NS16550_SERIAL are not the same. Are you having
problems in a stage with, or without DM_SERIAL enabled?

-- 
Tom
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