escc: emulate dip switch language layout settings on SUN keyboard

escc: emulate dip switch language layout settings on SUN keyboard

SUN Type 4, 5 and 5c keyboards have dip switches to choose the language layout
of the keyboard. Solaris makes an ioctl to query the value of the dipswitches
and uses that value to select keyboard layout.  Also the SUN bios like the one
in the file ss5.bin uses this value to support at least some keyboard layouts.
However, the OpenBIOS provided with qemu is hardcoded to always use an US
keyboard layout.

Before this patch, qemu allways gave dip switch value 0x21 (US keyboard),
this patch uses a command line switch like
"-global escc.chnA-sunkbd-layout=de" to select dip switch value. A table is
used to lookup values from arguments like:

-global escc.chnA-sunkbd-layout=fr
-global escc.chnA-sunkbd-layout=es

But the patch also accepts numeric dip switch values directly:

-global escc.chnA-sunkbd-layout=0x2b
-global escc.chnA-sunkbd-layout=43

Both values above are the same and select swedish keyboard as explained in
table 3-15 at
https://docs.oracle.com/cd/E19683-01/806-6642/new-43/index.html

Unless you want to do a full Solaris installation but happen to have
access to a Sun bios file, the easiest way to test that the patch works
is to:

qemu-system-sparc -global escc.chnA-sunkbd-layout=sv -bios /path/to/ss5.bin

If you already happen to have a Solaris installation in a qemu disk image
file you can easily try different keyboard layouts after this patch is
applied.

Signed-off-by: Henrik Carlqvist <hc1245@poolhem.se>
Message-Id: <20230623203007.56d3d182.hc981@poolhem.se>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[MCA edit: update unsigned char to uint8_t, fix spacing issues]
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>