puc support for a generic card (patch attached)

[Navdeep Parhar]

On Tue, Mar 3, 2009 at 11:51 AM, Navdeep Parhar <nparhar at gmail.com> wrote:
> On Tue, Mar 03, 2009 at 09:04:32AM -0800, Marcel Moolenaar wrote:
>>
>> On Mar 3, 2009, at 8:59 AM, John Baldwin wrote:
>>
>>> On Tuesday 03 March 2009 11:48:42 am Marcel Moolenaar wrote:
>>>>
>>>> On Mar 3, 2009, at 6:15 AM, John Baldwin wrote:
>>>>
>>>>>> diff -r 025cb00d19d7 sys/dev/puc/puc.c
>>>>>> --- a/sys/dev/puc/puc.c   Sat Feb 28 12:42:37 2009 -0800
>>>>>> +++ b/sys/dev/puc/puc.c   Mon Mar 02 12:21:07 2009 -0800
>>>>>> @@ -440,9 +440,6 @@
>>>>>>   sc->sc_dev = dev;
>>>>>>   sc->sc_cfg = cfg;
>>>>>>
>>>>>> - /* We don't attach to single-port serial cards. */
>>>>>> - if (cfg->ports == PUC_PORT_1S || cfg->ports == PUC_PORT_1P)
>>>>>> -         return (EDOOFUS);
>>>>>
>>>>> FWIW, the traditional reason for this is that we made the sio/uart
>>>>> or ppc
>>>>> drivers claim single port devices directly and only use puc for
>>>>> multiple-port
>>>>> cards.  I'm not sure if that should still be the case or not.
>>>>> Marcel, do you
>>>>> have an opinion?
>>>>
>>>> Yes :-)
>>>>
>>>> I explicitly added the test with that particular error code
>>>> to make it absolutely clear that puc(4) is not the driver
>>>> for single port cards. The reason being that it's pointless.
>>>>
>>>> There are 2 things that puc(4) facilitates in: resource
>>>> assignment and interrupt handling. For single port cards
>>>> there's nothing to distribute nor is there any interrupt
>>>> sharing. In other words: there's no value that puc(4) adds.
>>>> As such, uart(4) and ppc(4) can attach directly to those
>>>> cards and puc(4) does not have to be involved.
>>>>
>>>> BTW: Traditionally puc(4) was used to attach even to single
>>>> port cards. With the puc(4) rewrite I changed that, because
>>>> it was really a mixed bag. Some single-port cards were known
>>>> to puc(4) others to uart(4)/sio(4) or ppc(4). That typically
>>>> leads to confusion given that puc(4) is (still) not in GENERIC.
>>>> (i.e. why is this UART attached, but that one isn't, they're
>>>> both single port?)
>>>>
>>>> So, please do not apply the patch and instead add the IDs to
>>>> sys/dev/uart/uart_bus_pci.c...
>>>
>>> This sounds fine to me. :)  Navdeep, can you develop a patch for
>>> uart(4)
>>> instead and test that?
>>
>> BTW: I forgot to mention that puc(4) needs to back-off from this
>> particular card. That means that the catch-all that we have there
>> needs to be tweaked.
>>
>> So, the change to pucdata.c can still be made, but with a big
>> comment that states that the entry is added only to avoid puc(4)
>> from attaching to that particular 1-port card so that uart(4)
>> can claim it...
>
> OK, I'll keep this in mind and will modify the patch to have uart(4)
> claim the card and puc(4) ignore it.  I'll post it once I've tested
> it.

Reworked patch attached.  Works for me.

Navdeep

>
> Regards,
> Navdeep
>
>>
>> --
>> Marcel Moolenaar
>> xcllnt at mac.com
>>
>>
>>
>
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