On Mon, 2012-04-16 at 12:13 -0700, Randy Dunlap wrote:
> On 04/16/2012 09:02 AM, Onkar N Mahajan wrote:
>
> > Hello list,
> >
> > I am trying to understand the PCI functionality in Linux kernel.
> > What is the best way to start to understanding this - where to start
> > in the kernel code ? Books ? Manuals ?
> >
> > I started reading the code - where I am stuck in this function -
> > pci_check_type2() ; Wherein I am not able to get from where these values
> > 0xCFB,0xCF8,0xCFA are arrived at ? I guess these are port numbers , but
> > in which manuals can I find this all information.
> >
> > linux/arch/x86/pci/init.c:
> > static int __init pci_check_type2(void)
> > {
> > unsigned long flags;
> > int works = 0;
> >
> > local_irq_save(flags);
> >
> > outb(0x00, 0xCFB);
> > outb(0x00, 0xCF8);
> > outb(0x00, 0xCFA);
> > if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00 &&
> > pci_sanity_check(&pci_direct_conf2)) {
> > works = 1;
> > }
> >
> > local_irq_restore(flags);
> >
> > return works;
> > }
> >
> >
> > Please help me figuring out right manuals for this.
>
>
> The PCI spec (version 2.1 seems to be all I have available)
> discusses PCI Configuration Mechanisms and Special Cycles and
> these PCI config registers.
>
Thanks Randy , for your help. Can you please also guide me with
respect to good way to start understanding the PCI implementation
in Linux ?
-- Onkar
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