[U-Boot] [PATCH 1/2] serial: add skipping init option

[Simon Glass <sjg@chromium.org>]

Hi Jun,

On Fri, 22 Mar 2019 at 16:02, Jun Nie <jun.nie@linaro.org> wrote:
>
> Simon Glass <sjg@chromium.org> 于2019年3月22日周五 下午3:56写道：
> >
> > Hi Jun,
> >
> > On Fri, 22 Mar 2019 at 15:20, Jun Nie <jun.nie@linaro.org> wrote:
> > >
> > > add skipping init option to avoid corrupt data in console
> > > if serial is already initilized when u-boot start its excution.
> > >
> > > Signed-off-by: Jun Nie <jun.nie@linaro.org>
> > > ---
> > >  drivers/serial/Kconfig | 6 ++++++
> > >  1 file changed, 6 insertions(+)
> >
> > Could we use a device-tree property for this? Some UARTs have a
> > 'skip-init' property.
> >
> > Regards,
> > Simon
>
> Hi Simon,
>
> It is a good suggestion. But device tree is board specific, while the
> config is boot flow specific. For ATF -> OPTEE -> U-BOOT case,
> initialization should be skipped. Without earlier initialization from
> firmware, U-boot should do it by itself. So I need find a solution
> that is defconfig specific, instead of device tree specific.

So you want something that is flow-specific, I think. Your thinking is
that the defconfig specifies this. Is that because certain boards
require ATF/Optee?

Should we consider having a way to tell U-Boot that it is running from Optee?

Could the UART driver detect that the UART is already inited?

Regards,
Simon