RE: [PATCH] PCI serial card support

[Dugger, Donald D]

Bummer, I forgot about v2 vs. v3.  This means we have
a significant problem.  I can create a table to do the
base baud mapping without too much difficulty, there
are only about 153 non-standard devices to worry about,
it wouldn't be that hard to create a table for these
devices.

Automatically trying to identify the appropriate I/O
address for all the PCI cards out there is a much more
diffcult task that I don't want to try and do from
scratch.  The problem is that there are no standards
for which PCI BAR registers are used for which ports
on the serial cards.  The Linux driver has over 600
lines of customized code for over 100 different devices
to do this task.  Trying to duplicate that code from
scratch is rather unfeasible.

We're back to having the user manually specify the
I/O addres, then we can heuristically identify the
base baud with the ability to mnaually specify the
base baud if necessary.

--
Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
address@hidden
Ph: (303)443-3786

>-----Original Message-----
>From: address@hidden
>[mailto:address@hidden
>On Behalf Of Robert Millan
>Sent: Thursday, November 06, 2008 8:02 AM
>To: The development of GRUB 2
>Subject: Re: [PATCH] PCI serial card support
>
>On Wed, Nov 05, 2008 at 07:37:50AM -0800, Dugger, Donald D wrote:
>>
>> Hmmm, this is getting a litte more complex than I had hoped
>but so be
>> it.  The problem is that to do this you need more than just a PCI ID
>> to base_baud map, now you have to be able to enumerate
>serial devices,
>> both multi-port and multi-function, so you can match different
>> terminal ports to their resources.  The code to do this is
>moderately
>> complex but, fortunately, the code already exists in the
>Linux driver,
>> I can just copy that code.
>
>On one hand, the code might be GPLv2 only, and on the other
>GRUB maintainers require copyright assignments.  So I'm afraid
>this is likely not possible.
>
>> Also, I'd like to modify the `serial' command so that typing that
>> command with no arguments lists out the serial ports
>availale, I think
>> that would be a usefull capability.
>
>I'm thinking that it's somewhat odd that selection of serial
>port is done through the "serial" command instead of though
>the generic "terminal" one (I think this interface was
>inherited from GRUB Legacy).
>
>How would everyone feel about changing that?  So typing
>"terminal" could list serial0, serial1, etc.
>
>> I don't know anything about Express cards, if they sit on
>the PCI bus
>> with normal BDF's then there is no problem, if they
>interface through
>> some other means then supporting them will get interesting.
>
>Since this is for a legacy interface, I doubt there will be
>vendors manufacturing PCI Express cards for it.  USB is much
>more suitable for compatibility.
>
>--
>Robert Millan
>
>  The DRM opt-in fallacy: "Your data belongs to us. We will
>decide when (and
>  how) you may access your data; but nobody's threatening your
>freedom: we
>  still allow you to remove your data and not access it at all."
>
>
>_______________________________________________
>Grub-devel mailing list
>address@hidden
>http://lists.gnu.org/mailman/listinfo/grub-devel
>