Zhang Fuxin wrote:
>
> My irq dispatching code is very simple,it just read the IRR,count the first
> irq number and call do_IRQ.
> /*
> * the first level int-handler will jump here if it is a 8259A irq
> */
> asmlinkage void i8259A_irqdispatch(struct pt_regs *regs)
> {
> int isr, irq;
>
> isr = inb(0x20);
>
> irq = ffz (~isr);
>
> if (irq == 2) {
> isr = inb(0xa0);
> irq = 8 + ffz(~isr);
> }
>
> do_IRQ(irq,regs);
> }
>
OK, so the problem is not what I was thinking.
I don't have much clue here. I remember old i8259As have some timing issues
on fast cpus. Hopefully all the bridge chips are set up correctly ...
> >It is typically much easier to modify PCI device BARS so that they do coincide
> >with the same physical address. You can control that by using the correct
> >starting address for PCI MEM space in pci_auto.c resource assignment.
> It seems a good way to solve the ioremap problem and X problem.But virt_to_bus
> & bus_to_virt problem remains?
>
What is the virt_to_bus() problem? Is the address beyond 512MB (phy addr)?
If PCI mem (BUS) address is identical to phy addr, you should not have problem
unless the address is beyond 512MB.
BTW, virt_to_bus()/bus_to_virt() are deprecicated. See
Documentation/DMA-mapping.txt.
Jun
