[PATCH v5 05/28] efi: serial: Support arrow keys

[Simon Glass]

Hi Heinrich,

On Thu, 9 Dec 2021 at 12:44, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 12/4/21 07:56, Simon Glass wrote:
> > At present only the backspace key is supported in U-Boot, when running as
> > an EFI app. Add support for arrows, home and end as well, to make the CLI
> > more friendly.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
> >
> > (no changes since v1)
> >
> >   drivers/serial/serial_efi.c | 11 +++++++++--
> >   1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/serial/serial_efi.c b/drivers/serial/serial_efi.c
> > index 33ddbd6080c..0067576389d 100644
> > --- a/drivers/serial/serial_efi.c
> > +++ b/drivers/serial/serial_efi.c
> > @@ -24,6 +24,9 @@ struct serial_efi_priv {
> >       bool have_key;
> >   };
> >
> > +/* Convert a lower-case character to its ctrl-char equivalent */
> > +#define CTL_CH(c)            ((c) - 'a' + 1)
> > +
> >   int serial_efi_setbrg(struct udevice *dev, int baudrate)
> >   {
> >       return 0;
> > @@ -49,6 +52,7 @@ static int serial_efi_get_key(struct serial_efi_priv *priv)
> >   static int serial_efi_getc(struct udevice *dev)
> >   {
> >       struct serial_efi_priv *priv = dev_get_priv(dev);
> > +     char conv_scan[10] = {0, 'p', 'n', 'f', 'b', 'a', 'e', 0, 8};
> >       int ret, ch;
> >
> >       ret = serial_efi_get_key(priv);
> > @@ -63,8 +67,11 @@ static int serial_efi_getc(struct udevice *dev)
> >        * key scan code of 8. Handle this so that backspace works correctly
> >        * in the U-Boot command line.
> >        */
> > -     if (!ch && priv->key.scan_code == 8)
> > -             ch = 8;
> > +     if (!ch && priv->key.scan_code < sizeof(conv_scan)) {
> > +             ch = conv_scan[priv->key.scan_code];
> > +             if (ch >= 'a')
> > +                     ch -= 'a' - 1;
>
> This is not what a serial console would use in Linux. Just try U-Boot's
> conitrace command. If you use the following, we get compatibility with
> the rest of U-Boot:
>
> 1b 5b 32 7e - insert
> 1b 5b 33 7e - delete
> 1b 5b 35 7e - page up
> 1b 5b 36 7e - page down
> 1b 5b 41 - up
> 1b 5b 42 - down
> 1b 5b 43 - right
> 1b 5b 44 - left
> 1b 5b 46 - end
> 1b 5b 48 - home

That's more complicated since it requires the serial driver to convert
one character into multiple. We can always add it later if needed. But
this does command-line history, etc. working in the app.

Regards,
Simon