MPSAFE TTY schedule [uart vs sio]

[Marcel Moolenaar]

On Jul 5, 2008, at 5:24 AM, Takahashi Yoshihiro wrote:

> In article <29489C48-93A2-41D9-9EF1-5395A673A9B3 at mac.com>
> Marcel Moolenaar <xcllnt at mac.com> writes:
>
>>> The uart probably works for some 16550 based devices but does not  
>>> work
>>> for other one like multi-port devices.
>>
>> The design principle of uart(4) is that it does not know
>> about multi-port hardware. It controls a single serial
>> port only. For multi-port hardware you must have multiple
>> nodes on a bus or use an umbrella driver, such as puc(4),
>> quicc(4) or scc(4). Those drivers provide attachments for
>> every port.
>>
>> I suspect that support for multi-port devices is not to
>> hard to do on pc98...
>
> Many serial devices on pc98 use indirect I/O space, so resource
> management is quite complex.  Therefore, it may need more work you
> think.

I'm not sure I understand exactly what that means. Can you
elaborate?

> At the starting point, I have added CBus frontend and fixed console
> support for pc98.

Great, thanks!

Could you commit sys/pc98/include/bus.h and sys/pc98/pc98/busiosubr.c
at your earliest convenience. That code has to be in the kernel if
I were to work on the uart module.

Thanks,

-- 
Marcel Moolenaar
xcllnt at mac.com