[PATCH v5 08/20] x86: coreboot: Drop USB init on startup

[Bin Meng]

Hi Simon,

On Wed, Sep 20, 2023 at 9:37 PM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 20.09.23 13:50, Marek Vasut wrote:
> > On 9/20/23 09:19, Heinrich Schuchardt wrote:
> >> On 9/20/23 05:00, Simon Glass wrote:
> >>> This is very annoying as it is quite slow on many machines. Also, U-Boot
> >>> has an existing 'preboot' mechanism to enable this feature if desired.
> >>>
> >>> Drop this code so that it is possible to choose whether to init USB or
> >>> not.
> >>>
> >>> Use the existing USE_PREBOOT mechanism instead.
> >>>
> >>> Signed-off-by: Simon Glass <sjg at chromium.org>
> >>> ---
> >>>
> >>> Changes in v5:
> >>> - Make use of the uSE_PREBOOT mechanism
> >>>
> >>>   arch/x86/cpu/coreboot/Kconfig    | 1 +
> >>>   arch/x86/cpu/coreboot/coreboot.c | 4 ----
> >>>   2 files changed, 1 insertion(+), 4 deletions(-)
> >>>
> >>> diff --git a/arch/x86/cpu/coreboot/Kconfig
> >>> b/arch/x86/cpu/coreboot/Kconfig
> >>> index b97c27790419..178f8ad18162 100644
> >>> --- a/arch/x86/cpu/coreboot/Kconfig
> >>> +++ b/arch/x86/cpu/coreboot/Kconfig
> >>> @@ -25,6 +25,7 @@ config SYS_COREBOOT
> >>>       imply FS_CBFS
> >>>       imply CBMEM_CONSOLE
> >>>       imply X86_TSC_READ_BASE
> >>> +    imply USE_PREBOOT
> >>
> >> For automatic initialization of the PCI bus we have CONFIG_PCI_INIT_R.
> >> Wouldn't it be preferable to also have a CONFIG_USB_INIT_R instead of
> >> relying on console commands in CONFIG_PREBOOT?
> >
> > I'd much prefer 'preboot=usb init' or whatever console command, since
> > this is not hard-coded into the U-Boot binary and can be overridden by
> > user if the 'usb init' is inconvenient/unnecessary/... without replacing
> > and/or rebuilding the U-Boot binary.
>
> Just for the record this means using CONFIG_PREBOOT:
>
> include/env_default.h:
>
> #ifdef  CONFIG_PREBOOT_DEFINED
>      "preboot="    CONFIG_PREBOOT    "\0"
> #endif
>
> Thank you for the clarification.

Will you update the coreboot documentation to mention the PREBOOT
mechanism to initialize USB so that a USB keyboard can be used as the
input for the U-Boot console?

Regards,
Bin