Re: [LinuxBIOS] Building an irq table - Help

Quoting Marc Jones :
> [e-mail] wrote:
> > Quoting Marc Jones :
> > > [e-mail] wrote:
> > > > Ok I am a little confused on how to tell what devices are what in  
> > > >   irc_tablec.c
> > > > How do I tell?? Also where does the value for the "bitmap" come from?
> > > >
> > > > Thanks for your help - Joe
> > > >
> > > > /* bus,     dev|fn,
> > > > {0x01,(0x08<<3)|0x0,
> > > > {0x00,(0x1f<<3)|0x0,
> > > > {0x00,(0x02<<3)|0x0,
> > >
> > > Joe,
> > > There is some good information here:
> > > http://linuxbios.org/index.php/Creating_Valid_IRQ_Tables
> > > http://www.microsoft.com/whdc/archive/pciirq.mspx
> > >
> > > Your bus/dv/fun should match the devices found when you do an lspci.
> > > The value for the bitmap is what IRQs are available on that INT#.
> > > Theses are typically 10 and/or 11 but could be any shareable IRQ.
> > >
> > > Marc
> > >
> > > 0xDDDDFFFF, LNK, 00, GSI
> > >
> > > DDDD is PCI DEV, FFFF is function, LNK is PCI link - so LNKA B etc...
> > > Next parameter is 00 if you do not support legacy PIC routing at all.
> > >
> > > Last parameter is global interrupt NR.
> > >
> > > Hope it helps,
> > >
> > > Rudolf
> >
> > Thanks for your help Marc and Rudolf. I have been looking through   
> > most of the other irq_tables.c from different mainboards and it   
> > seems like on most of them the "fn" is 0x0 (like above). Is this a   
> > bug in getpir?? So do I need to manually change these to the   
> > correct functions?
> >
> > I understand where the "link" comes from. These are set in the LPC   
> > Bridge registers, but where does the value for the "bitmap" come   
> > from? Mine eithor say 0xded8 or 0x0000?? The 0x0000 means it is not  
> >  routed right? But I don't get where the 0xded8 comes from?
> >
> > I just attached my irq_tables.c created from getpir so you can see   
> > what I mean.
> >
> > Thanks - Joe
>
> The bitmap is means for every bit that is set can be routed as an IRQ.
> So, bit 10 and 11 set means that link can be programmed to IRQ 10 or
> 11. The bitmap would be 0x0c00.
>
> 0xded8 = 1101111011011000
>          |          ||_IRQ3
>          |          |__IRQ4
>          |_IRQ15
>
> Marc

Oh ok, that makes perfect sense. So it looks like in 0xded8 they  
pretty much made the range open to as many irqs available to PCI. What  
is the benifit of using such a large range? Just lazy coding if they  
are all the same (0xded8)?

Thanks - Joe