[OpenBIOS] usb driver to support usb keyboard

[BALATON Zoltan]

On Wed, 7 May 2014, Mark Cave-Ayland wrote:
> First place I would look at is in drivers/pci.c and drivers/pci-database.c to 
> make sure that the USB host is detected in the firmware tree - it should 
> appear without any properties. Next download the IEEE1275 PCI bindings and 
> have a look at the words there.

I've already looked at pci-database.c for the C driver from coreboot's 
libpayload. The USB controller was detected but printed "cannot manage" as 
there was no driver. I could add a callback to call the init function of 
the driver. I assume for a Forth driver should replace this to call into 
Forth like the vga driver does.

> Probably the first place to start is getting the PCI config space accesses 
> working; for this you will probably need to implement some Forth wrappers 
> around C for the PCI config space access functions from the PCI bindings.

I don't see this yet. Can you give me some more details like which Forth 
words should be implemented by wrapping which C functions and an example 
of such implementation?

> In OpenBIOS, files are added into the build.xml file which generates a set of 
> Makefiles when running the switch-arch script.

I've found this but I don't know how to add files for a driver. The vga 
driver is in build.xml like this:

  <fcode source="vga.fs" name="QEMU,VGA.bin" condition="DRIVER_VGA" />

What should be the name? Can I just come up with something or are there 
some rules to follow?

> The .bth files are probably used to create FCode blobs, much in the same way 
> as the toke utility from the OpenBIOS fcode-utils does. Take a look at 
> drivers/build.xml and in particular the vga driver to see how this is done, 
> as this was a driver I converted over from C.
>
>> The ohci.bth file looks like this:
>> 
>> ---begin---
>> purpose: Load file for OHCI HCD
>> 
>> command: &tokenize &this
>> build-now
>> 
>> silent on
>> 
>> begin-tokenizing ohci.fc
>> 
>> FCode-version2
>> 
>> " ohci" encode-string " device_type" property
>> 
>> fload ${BP}/dev/usb2/hcd/ohci/loadpkg.fth
>> 
>> end0
>> 
>> end-tokenizing
>> ---end---
>> 
>> and the hcd/ohci/loadpkg.fth referenced here contains more fload
>> commands that load the other parts. What is the equivalent in OpenBIOS's
>> Forth to do this?
>
> Instead of fload, you should be able to use include instead (see 
> forth/bootstrap/start.fs). And for tokenizing, you simply run the Forth 
> source code through fcode-utils' toke command.

OK, I'll try to use include instead of fload and see what errors I get and 
if I can make sense of them.

> Also once you start to get a feel for the work and think it's viable, we 
> should get Stefan to make sure he's okay with the OpenFirmware license with 
> respect to OpenBIOS' GPLv2.

There's not much I can do about that licensing so feel free to ask now, 
it's better to know upfront if the patch cannot be accepted. (Although 
I've checked on gnu.org that the BSD style license should be compatible 
with GPLv2.)

Regards,
BALATON Zoltan